EXPERIMENTAL 
ESSAYS. EXPERIMENTAL 
ESSAYS 
ON THE FOLLOWING 
SUBJECTS: 
I. On the Fermentation of 
Alimentary Mixtures. 
II. On the Nature and 
Properties of Fixed Air. 
III. On the refpedlive 
Powers, and Manner of 
Acting, of the different 
Kinds of Antifeptics. 
IV. On the Scurvy; with 
a Propofal for trying 
new Methods to prevent 
or cure the fame, at 
Sea. 
V. On the Diffolvent 
Power 
Illuflrated with Cppper-PlateS^ 
By DAVID MACBRIDE, Surgeon. 
LONDON: 
printed for A. Millar, in the Strand. 
/ 
MDCCLXIY, The wonderful and fecret Operations of Nature are fo 
involved and intricate, fo far out of the Reach of our 
SenfeSj as they prefent themfelves to us in their na- 
tural Order, that it is impofiible for the moft faga- 
cious and penetrating Genius to pry into them, un- 
lefs he will be at the Pains of analyfing Nature by 
a numerous and regular Series of Experiments, which 
are the only folid Foundation whence we may reafon- 
ably expert to make any Advance in the real Know- 
ledge of the Nature of Things. Hales» THE 
preface. 
TH E general purpofe of the 
following eflays is to fhew* 
that there is another principle in 
matter befide thofe which are com- 
monly received; and that it is upon 
this principle* forming the cement* 
or bond of union, that the firmnefs, 
found nefs, and perfedt coheflon of bo- 
dies* chiefly depend,  The P RE FACE. 
It being the author’s intention to 
apply this dodtrine particularly to 
medicine, he begins his inveftigation 
by tracing the progrefs of digeftion, 
and fhewing that the principle above 
hinted at is received into animal bo- 
dies by the way of the chyliferous 
canals; and this makes up the fub]e6t 
of the firft effay, and of fome part of 
the fecond. 
This point being proved by a 
<r • 
number of experiments, and illuf- 
trated by fome practical obfervations, 
he goes on to fhew, from experi- 
ment alfo, that animal fubdances be- 
come putrid from the lofs of the 
above-mentioned principle ; feeing, 
that putrefadlion is found to arife 
from the refolution and difunion of The PREFACE. 
the feveral conftituent particles; and 
offers a new theory for explaining 
the immediate caufe of that degree 
of putrefaction* which often takes 
place in the living body. Here an 
opportunity is taken of introducing 
fome experiments, in order to deter- 
mine whether or not putrid animal 
fubftances are to be regarded as al- 
caline: and it appearing from thefe 
that fuch fubftances are in reality of 
an alcaline nature, and that fome 
writers of very great note have been 
mis-led into a contrary opinion, pro- 
bably from obferving that alcalies re- 
fill putrefaction ; he then proceeds, 
in the third effay, to examine, expe- 
rimentally, the power of antifeptics 
in general; and finds that this de- 
pends, for the moft part, on re-  The PREFACE. 
(training the flight of the cementing 
principle. 
An enquiry then commenceth 
concerning the power of different 
things to reftore foundnefs and fweet- 
nefs to fubftances already putrid; 
and it is fhewn, likewife from expe- 
riment, that this may be accom- 
plifbed by reftoring the cementing 
principle. 
This naturally leads to a confi- 
deration of the mofl efle&ual me- 
thods of curing putrid difeafes, which 
is alleged to depend greatly on the 
application of fuch things as are 
known to be capable of furnifhing a 
large proportion of the principle fo 
often mentioned; and this is parti- The PREFACE. 
cularly exemplied in the cure of the 
fea-fcurvy; a dileafe wherein the mals 
of fluids is evidently in a ftate of pu- 
trefaction. 
In confequence of this hypothe- 
fis, a propofal enfues for trying new 
methods to prevent or cure the fcur- 
vy, at fea; and this affords matter 
for a fourth eflay, to which is an- 
nexed a very accurate account of 
that molt deftruCtive difeafe, ex- 
tracted from the writings of John 
Woodall, an old Englilh furgeon, 
whofe works feem to be but very lit- 
tle known. 
• / 
The fifth effay contains a num- 
ber of mifcellaneous experiments and 
obfervations, all tending to a further  The PREFACE. 
proof of what had been advanced in 
the lour preceding ones; and con- 
cludes with laying down eafy and 
expeditious methods of diffolving in 
water camphor, and all kinds of re* 
finous fubftances. 
The foundation of the foregoing 
dodrine having been laid near forty 
years ago, by the celebrated Dodor 
Hales, and, of late, much improved 
by Dodor Black, Profeffor of Me* 
dicine of Glafgow, it will be proper 
that the reader be thoroughly ac- 
quainted with the Analyfis of Air* 
in the firfl: volume of Hales’s Sta~ 
ticks; and with the experiments on 
Magnefia, in the fecond volume of 
the Edinburgh Phyfical and Literary 
Eflays i as alfo with the cxperi- The PREFACE. 
ments made by Doctor Pringle, 
and which are to be found in the 
Philofophical Tranfadtions, or in the 
Appendix to that learned phyfician's 
Obfervations on the Difeafes of the 
Army ; the following papers being 
deftgned as a fequel to all the three 
writers juft now mentioned, 
ESSAY ESSAY I. 
P N T H E 
>A «\\\ . , v. » a - *''* - , '■ ‘ '•* ‘ '' ' 
FERMENTATION 
/ v ,‘t , ’ * - i; „ 
O F 
ALIMENTARY MIXTURES. The mam bujinefs of natural philofophy is to 
argue from phenomena, without feigning 
hypothefes. Newton, ESSAY I. 
ON THE 
Fermentation of Alimentary 
Mixture s. 
TH E old chemifts believed, that all 
the true fpontaneous changes, or 
tranfmutation of bodies, were the 
effeCts of fermentation; but Boerhaave, dis- 
liking fo enormous an extenfon of terms, 
retrained it within very narrow limits, and 
would fuffer nothing to be called Ferment- 
ation which did not produce either an ar- 
dent fpirit, or an acid; thus entirely con- 
fining it to what are ufually called the vi- 
nous and acetous flages, and altogether re- 
jecting the putrefaftive, as looking on pu- 
trefaction to be a quite different procefs, 
and no way allied to fermentation. 
But this reftriCtion, which was meant 
for the fake of clearnefs and precifion, has 
rather introduced confufion, with regard to 2 
On the Fermentation of 
the term putrefaction. This word, in its 
common acceptation, is always understood 
to imply a plain tendency to deftruCtion in 
bodies, accompanied with every fign of 
rottennefs and offenfivenefs: and, accord- 
ingly, we often meet with it in writers, in 
this when perhaps, in the very fame 
page, we Shall be told, that the aliment is 
prepared for nourishing the human body 
by putrefaction; that motion, life, and heat 
are communicated to the fluids by putre- 
faction ; and that nature throws off mor- 
bific matter from the constitution by the 
means of putrefaction. 
The later chemiSts, therefore, who have 
reduced this branch of natural philofophy 
to a more intelligible and methodical fyf- 
tem, than that of the great man juft now 
mentioned, approach nearer to the ancient 
opinion, and define fermentation to be an 
“ intejiine motion, which arijing fpontane- 
<( oufly among the infenjible parts of a body, 
<( produceth a new difpofition, and a different 
“ co?nbination of thofe parts'" (Macquer.J 
From this definition it is plain, that a 
great number of the natural changes which 
daily take place in the animal and vegeta- 
ble kingdoms, Should be looked on as fo Alimentary Mixtures. 
many modes of fermentation and that, 
in particular, the digeftion of our food 
ought to be regarded as a fermentatory 
procefs. 
The experiments already made by the 
very learned and ingenious Dr* Pringle 
feem fufficient to convince every unbiaffed 
reader of the truth of this theory; which, 
if we confider the matter with any de- 
gree of attention, we fhall find to be ab- 
solutely neceffary, in order to bring about 
that new difpoiition, and that different 
combination, of the infenfible parts of 
the alimentary fubftances which enable 
the immenfe variety of difcordant mix- 
tures, that enter the compofition of our 
food, to depart fo far from their original 
natures as to become one mild, fweet, 
and nutritious fluid; for this demands 
a great deal more than mere mechanical 
mixture and diffolution, which is the moft 
that the common theories * of digeftion 
extend 
* Here we muft except Hoffman's theory j for he 
infills much on the compleat change that the aliment 
undergoes in the firft paflages •, and makes digeftion a 
mere fermentatory procefs; as may be feen at large in On the Fermentation of* 
extend to; fince they do not feem exprefiy 
to require, nor indeed fuppofe, fuch an 
abfolute change to be wrought* in the 
firft paffages, on the nature of the differ- 
ent kinds of food as would render them 
fufceptible of that firm union, and that 
ftrong attraction, by the means of which 
they become, fo foon, one and the fame 
fubftance with the body into which they 
are received. 
It alfo appears pretty plain, from Dr. 
Pringle s experiments, that there is fome- 
what generated, or fet free, during the 
firjl Jlage of the fermentation of animal 
and vegetable mixtures, which hath a 
power of correcting putrefaction. But, in 
order to obtain ftill further proofs con- 
cerning this particular point, as well as to 
gain a more thorough knowledge of fer- 
mentation in general, I determined to re- 
peat fome of the doctor’s experiments, and 
to try fuch others as I thought had the 
greatefl tendency towards an illuflration of 
both. 
his chapter de Alimentorum Solution & Saliva Ufa, and 
the three fucceeding ones. Table I. Of ALIMENTARY MIXTURES. 
Mixtures 
of 
At the end of 6 hours. 
At the end of 22 hours. 
At the end of 30 hours. 
At the end of 46 hours 
After 54 hours. 
At the end of 4 days. 
(i) Bread 
and water. 
Shews no figns of in- 
teftine motion. 
Still remains perfectly 
quiet. 
Still at reft. 
Still at reft. 
Still at reft. 
A fournefs now per- 
ceivable. 
(2) Bread, 
mutton, 
and water. 
Fermentation fairly be- 
gun j fmell of the mix- 
ture perfectly fweet. 
Fermenting now very 
brifkly. 
Brifk ; the fmell of the 
mixture perfectly fweet 
and a little pungent. 
Brifk and fweet; much 
froth at top. 
Brifk and fweet. 
Fermentation appeared 
to be now very near 
over; liquor fweet, both 
to the fmell and tafte. 
(3) The 
fame,with 
frefh juice 
of lemons. 
In brifk fermentation ; 
perfedtly fweet; fmell 
of the lemon juft per- 
ceivable. 
Very brifk; immerfed 
a fmall bit of putrid 
mutton in this mixture. 
Brifk; no fmell now 
perceivable in the bit 
of putrid mutton, but 
that of the mixture. 
Still fermenting; the li 
quorclearandfweet; re 
moved the bit of mutton 
and hung it up to dry, 
it being perfe&ly fweet. 
Motion ftopt ; the bit 
of mutton dried and 
fweet. 
Uiftilled this mixture ; 
an almoft infipid 
phlegm, with rather a 
vinous, than an acid 
tafte, was the produce. 
(4) The 
fame,with 
fpinnage. 
In brifk fermentation ; 
a heavy kind of fw'eetifh 
fmell, not unlike that 
of the fenugreek feed. 
Very brifk; fufpended 
a little bit of putrid mut- 
ton in the phial,fo as not 
to touch the mixture. 
Brifk; no fmell in the 
bit of mutton, but that 
of the mixture. 
Fermentation appeared 
to be almoft over ; li- 
quor clear and fweet; 
removed this, and the 
phial with lemon-juice, 
to a cool place, and 
corked them clofe ; 
hung up the mutton. 
Motion ftopt; the bit 
of mutton dried and 
fweet. 
The fmell of this mix- 
ture, before diftillation, 
wasalittle inclinableto 
the cheefey, and the 
phlegm obtained by di- 
ftillation had a fmall de- 
gree of pungency, with 
the fame rancid flavour. 
(5) The 
fame,with 
water- 
crefles. 
Motion not fo brifk as 
in the two laft, but con- 
fiderably more fo than 
in the fimple mixture ; 
fmell of the herb but 
barely perceivable. 
Very brifk; poured half 
an ounce of frefh ox- 
gall into the phial. 
Not fo brifk as in the 
morning ; perfe&ly 
fweet. 
Liquor clear and fweet; 
ftopt the phial well, and 
removed it to a cool 
place; the mixture taft- 
ed a little of the gall. 
Motion ftopt. 
This mixture was 
fweet, with the fenu- 
greek flavour. 
(6) The 
fame, with 
fome pu- 
trid ani- 
mal li- 
quor. 
... 
Motion greater in this 
phial than in any of the 
others, with a thick 
fcum and froth on the 
furface; not theleaft ill 
fmell to be perceived, 
tho’ the putrid liquor 
Was exceedingly offen- 
five when firft added. 
Very brifk ; tho’ in the 
coldeft place of all the 
phials. (Every one of 
the mixtures were now 
perfectly fweet, and had 
loft the peculiar fmell 
of the herbs, he.) 
Brifk and fweet. 
Still in brifk fermenta- 
tion, and fweet. 
Removed the phial, 
and ftopt it clofe ; fer- 
mentation now almofl 
over. 
The mixture was now 
upon the turn; a little 
fournefs juft perceiva- 
ble. 
To face page 5. Alimentary Mixtures. 
To fulfil thefe Intentions, I made up the 
fix following mixtures: 
i . Bread and water. 
2. Bread and boiled mutton, beat up 
with the requifite quantity of water. 
This was called the fimple fermentative 
mixture. 
3. Four ounces of the fimple fermenta- 
tive mixture, with two drachms of frefli 
lemon-juice. 
4. Four ounces of the fimple mixture, 
beat up with an ounce of fpinnage. 
5. Four ounces of the fimple mixture, 
with an ounce of green water-crelfes. 
6. Four ounces of the fimple mixture, 
with two drachms of a very fetid liquor 
that lay about putrid mutton. 
These mixtures, being put into phials 
not clofely Hopped, were all placed in a 
moderate degree of heat, on the top of a 
fand furnace, wherein a retort was at work, 
on a procefs which required a continual 
fire for three or four days. 
In order to have a fynoptical view of the 
progrefs from time to time, I formed the 
annexed table, No. I. wherein I minuted 
down the feveral appearances, exactly as 
they fhewed at each examination; but the On the Fermentation of 
general progrefs of the five mixtures that 
fermented was as follows: 
In three or four hours the inteftine mo- 
tion was evident; and foon after all the 
folid part of the mixtures rofe to the top; 
bubles of air, and a thick fcum, formed 
on the furface ; a vapour, with fome de- 
gree of pungency, and which extinguished 
fire, now began to difcharge itfelf, and the 
peculiar finell of the feveral ingredients 
having gradually gone off, a fweetifh kind 
of flavour, in fome of the mixtures not 
unlike that of fenugreek feed, fucceeded 
to it; while the motion becoming very 
briflc, little pieces of the folid matter 
every moment fell to the bottom of the 
phials. 
This inteftine motion continued for the 
periods exprefled in the table; and by the 
time that it had ceafed, the mixtures were 
clear, great Share of what formerly floated 
having now fallen down ; they were alfq 
perfectly fweet, and fuch of them as were 
committed to diftillation, fent over a wa- 
ter, or phlegm, with a flight degree of 
pungency, and of the fame fweetifh fmell 
of the mixtures, excepting one, that had 
a little of the rancid, or cheefy flavour. Alimentary Mixtures. 
Thus we fee that the appearances, dur- 
ing the time that thefe mixtures were fer- 
menting, are exactly like thofe which at- 
tend the working of the fweet vegetable 
liquors; and the difference feems only to 
lie in the product of the fir]} fiage—which 
we find does not, like thefe liquors, yield 
an ardent fpirit by dill illation; altho’ there 
are fome reafons for believing that mix- 
tures of animal and vegetable fubflances, 
if fermented together in large quantities, 
would produce a liquor of an intoxicating 
quality. 
Travellers of good credit affure us, 
that there are among the great variety of 
Tartar tribes inhabiting the wilds of Sibe- 
ria, fome who have methods of obtaining 
an intoxicating liquor from milk, which, 
in all probability, is brought to ferment by 
the admixture of fome putrid animal fub- 
flance, which Dr. Pringle finds (and the 
fame thing may be feen in the foregoing 
table, at No. 6) to encreafe very power- 
fully the tendency to fermentation, either 
in milk, or in the common fermentative 
mixtures. And others of thefe northern 
nations make themfelves drunk with a 
moil naufeous liquor, made by allowing On the Fermentation of 
fifh and water to ferment in holes dug in 
the earth, and lined with the bark of the 
birch-tree. 
However, until this matter be more 
fully proved, and that it can be plainly 
jfhewn that thefe mixtures do produce an 
intoxicating liquor, or an ardent fpirit, it 
will be proper, as well as more clear and 
comprehenfive, to denominate the three 
Stages of fermentation, either limply, JirJi, 
fecond, and third; or, if it be more agree- 
able, fweet, four, and putrid ; and charac- 
terife them by their feveral products : The 
firfl, or fweet Stage, being two fold, as 
yielding, id:, a fweet, agreeably pungent, 
inebriating liquor ; or, 2dly, a fweet (i. e. 
fweet, as oppofed to four, and putrid) li- 
quor, which is not inebriating. The fe- 
co?id, or four Stage, as turning the fubjedt 
manifestly four, and yielding an acid phlegm 
upon diftillation. And the third, ox pu- 
trid, when the texture of the fubflance fer- 
mented is fairly destroyed, and having loSt 
its original characters of taSte, colour, and 
fmell, it becomes fetid, rotten, and offen- 
five; and if committed to distillation, yields 
neither an inflammable fpirit, nor a fweet 
phlegm, nor an acid; but a Sharp pungent Alimentary Mixtures. 
9 
liquor, being a folution of a volatile alca- 
line fait, nearly fimilar to that fait which 
may be obtained, by the force of violent 
heat, from animal fubftances, without fuf- 
fering them firft to become putrid *. 
Th{s diviiion, and manner of denomi- 
nation, will be found to correfpond with 
appearances, and will perhaps comprehend 
all fermentable fubftances whatfoever; 
whereas the terms vinous, fpirituous, and 
acetous, can, with ftritft propriety, be ap- 
plied to the fermentation of the fweet ve- 
getable liquors only, which yield, in their 
* When it is faid, that a volatile alcali may be ob- 
tained from putrid fubftances by diftillation, it is to be 
remarked, that whoever makes the experiment, muft 
not fuff'er fuch fubftances to remain too long before 
they are diftilled, unlefs kept in clofe veflels ; becaufe 
the volatile alcali, which is the offspring of putrefac- 
tion, is diftipated as faft as it is generated, infomuch 
that, at length, nothing is left behind but an infipid 
water, or a folid matter, being an earth fimilar to com- 
mon mould. 
And it is in this way, that ftinking water, after fome 
time, becomes fweet; the volatile alcali, generated by 
the putrefa&ion of the animal and vegetable fubftances 
at firft contained in the water, being, after a while, 
entirely diftipated, leaves the remainder without any 
difagreeable fmell. On the Fermentation of 
firft and fecond ftages, an inebriating, in- 
flammable fpirit, and vinegar. 
The reader, upon looking into the ta- 
ble, will find, that there were two little 
bits of putrid mutton put into two of the 
phials, while the mixtures were ferment- 
ing ; and that thefe bits of flefh were ren- 
dered fweet. This was owing to the ac- 
tion of the vapour, fet free during the fer- 
mentation ; and, as will be fhewn at large 
in another place, the vapour from the fweet 
vegetable liquors produceth the very fame 
effed. 
It was found, that the vapour from the 
mixtures agreed like wife in another cir- 
cumfiance with the Subtile Gas, as it was 
termed by the old chemifts, namely, that 
of extinguifhing fire ; and, I dare fay, it 
would alfo fuflfocate animals. But notwith- 
ftanding that this vapour, if applied in 
large quantity to the lungs, might prove fo 
very pernicious, yet it does not by any 
means follow, that it muft neceflarily pro- 
duce the fame deadly effect, if pent up in 
the bowels : We may be very certain that 
it does not; for if that were to be the 
cafe, people would be in very great dan- Alimentary Mixtures. 
ger after almoft every meal they eat, fince 
it is evident, that the vegetables moft com- 
monly ufed as a part of our food, when 
mixed, either with flefh, or with the na- 
tive animal juices, actually do raife a fer- 
mentation in the firft paffages, which muft 
of courfe produce a great deal of this ac- 
tive vapour. 
There is not fufficient ground, there- 
fore, for acquiefcing in a theory which 
hath fometimes been taught, attributing 
the fudden death of people who had eaten 
largely of fruit, or the like, to the action 
of this fubtile fpirit, as fuppofing it to be- 
numb and deprive the nerves of all power 
and influence. 
If this hypothecs were not ill founded, 
perfons in thefe circumftances, who have 
been refcued from death by the timely ex- 
hibition of an emetic, would not recover 
themfelves fo immediately as they are 
known to do; which fhews that the dif- 
trefs muft have been occafioned merely by 
the over diftenfion of the ftomach; for had 
the pernicious vapour once fairly made its 
deadly impreffion, emptying the ftomach 
would avail but little s and, if the party 
recovered at all, it would be but flowly, 12 
On the Fermentation of 
and not without much confequent relaxa- 
tion, and weaknefs of the paralytick kind *. 
Therefore, inftead of imagining this 
active and fubtile vapour to be productive 
of any harm in the body, it will appear 
hereafter, that there are very ftrong rea- 
fons for believing, that it is the grandpre- 
fewer of animal fluids from putrefaction 
that it attempers acrimony; is a principal 
agent in nutrition and, perhaps, contri- 
butes fomewhat to animal heat -f. 
Since things of fuch different natures 
as bread, lemon-juice, fpinnage, and wa- 
ter-creffes, all run with equal facility into 
fermentation, we might almofl: venture to 
conclude that any vegetable, when mixed 
with an animal fubftance, and furnifhed 
with the requiflte quantity of water, will 
likewife ferment, But to try this matter 
flail farther, in a few days after going thro* 
the foregoing experiment, I mixed up no 
lefs than twenty-one of this kind of mix- 
* Vide Boerhaavii Elementa Cbemia, tom. ii. p. 180 
y 181. 
t Dr. Pringle found the thermometer raifed three 
degrees by a fermenting mixture of bread, beef, and 
faliva ; fo that there appears to be fomc ground for this 
conje&ure. Alimentary Mixtures. 
13 
tures, moft of them being in quantity about 
four ounces; viz. 
1. Bread and water. 
2. The fame, with two drachms of faliva. 
3. Bread and water, with green herbs. 
4. The fame, with two drachms of faliva. 
5. Flour and water. 
6. The fame, with two drachms of faliva. 
7. Green herbs and water. 
8. The fame, with two drachms of faliva. 
9. Flour and water, with green herbs. 
(The green herbs were fpinnage, water- 
creffes, and onions, equal parts, beat up 
together. 
10. The fimple fermentative mixture. 
(i. e. Flefh meat, bread, and water.) 
11. Flour and flefh meat, with water. 
12. The fimple mixture, with about an 
ounce of green water-creffes. 
13. The fimple mixture, with an ounce 
of fpinnage. 
14. The fimple mixture, with an ounce 
of green onions. 
15. The fimple mixture, fix ounces; le- 
mon-juice, one ounce. 
16. The fimple mixture, fix ounces ; 
frefh wort, one ounce. On the Fermentation of 
17. The fimple mixture, fix ounces j 
ftrong folution of fugar,. one ounce. 
18. The fimple mixture, fix ounces ; 
ftrong folution of honey, one ounce. 
19. The fimple mixture, fix ounces; vi- 
negar, one ounce. 
20. The fimple mixture, fix ounces ; 
brandy, one ounce. 
21. A fimple fermentative mixture, made 
with fait beef. 
These mixtures were all made up at 
night, and lay fourteen hours before they 
were placed in a fand bath, where it was 
intended to have kept up a moderate de- 
gree. of heat. 
They were all placed in the fand at ten 
o’clock in the morning, being then, every 
one of them, perfectly fvveet. The fire 
was now ordered to be kindled : In fix 
hours I went to fee how things were going 
on, and was greatly vexed and difappointed 
to find that the fire, through inattention of 
the fervant entrufted with the care of it, 
had been made fo ftrong that the mixtures 
were all in a much fairer way to boil than 
to ferment. I therefore removed the phials 
from the fand, and reckoned all this as fo 
much loft labour, not expecting, after hav- Table II. Of ALIMENTARY MIXTURES. 
MIXTURES of 
1. 
2. 
(i) Bread and water. 
No figns of inteftine motion. 
Appears not to have ftirred at all; four. 
(2) The fame, with abou 
3ij of faliva. 
No figns of motion. 
Appears to have fermented, there being froth at 
top; now at reft, and quite fweet. 
(3) Bread and water, wit! 
fome green herbs; 
No figns of motion. 
Had not ftirred ; fmell of the herbs ftrong. 
(4) The fame, with 3ij 0 
faliva. 
f 
Motion fairly begun. 
Had fermented ; now at reft ; fweet, of the fenu- 
greek fmell. 
(15) Flour and water. 
No figns of motion. 
Had not ftirred ; not four. 
(6) The fame, with 3ij of 
faliva. 
No figns of motion. 
Had fermented; now at reft ; fmell fweet, like the 
fenugreek. 
(7) Green herbs and water. 
No figns of motion. 
Had not ftirred ; lmell ot the nerbs ftrong. 
(8) The fame, with 3ij of 
faliva. 
Motion beginning 
Had fermented ; fcum on the furface; fmell fweet, 
like the fenugreek. 
(9) Boiled mutton, with 
fome green herbs. 
No figns of motion. 
Had undergone the fermenting motion, tho’ now 
at reft, the mutton and herbs having all rifen to 
the furface. 
(10) Bread and boiled mut- 
ton, with water. 
Motion juft perceivable. 
Still in motion ; great fcum at top; fmell fweet, 
like the fenugreek. 
(11) Flour and boiled mut- 
ton, with water. 
Motion fairly begun. 
Still at work; the fmell perfectly fweet. 
(12) Bread and mutton, 
with water-crefles. 
Motion begun ; fmell of the 
herb not perceivable. 
Had wrought brifkly ; now on the decline; fmell 
of the fenugreek ftrong. 
(13) The fame, with fpin- 
nage. 
Motion begun ; fmell of the 
herb not perceivable. 
Still at work; fmell fweet, exactly like the pre- 
ceding. 
(14) The fame, with green 
onions. 
Motion fairly begun; fmell of 
the onion yet ftrong. 
Did not appear to have wrought much; fmell of 
the onion ftill ftrong. 
(15) The fame, with juice 
of lemons. 
No motion begun. 
Had fermented; fmell of the lemon entirely gone; 
mixture fweet. 
(16) The fame, with frefh 
wort. 
Motion fairly begun. 
Not yet quite at reft; fweet; peculiar fmell of the 
wort now loft. 
(17) The fame, with fugar 
and water. 
Motion begun ; not fo brifk 
as the preceding. 
At reft ; fourifh, with a little of the cheefej 
fmell. | 
(18) The fame, with honey 
and water. 
Motion begun, and as ftrongas 
in the mixture with the wort. 
Mixture fweet, and at reft; appears to have 
wrought pretty brifkly. 
(19) The fame,with vinegar. 
No motion. 
Does not appear to have ftirred. 
(20) The fame,with brandy. 
No motion, 
Does not appear to have ftirred. 
(21) Salt beef and bread, 
with water. 
No motionf 
Appears to have wrought, the lighter parts, and 
much fcum, being on the furface; fweet, like 
the mixture with the frefh meat. Alimentary Mixtures. 
15 
ing been fo much over-heated, that they 
would ferment at all. However, in fix 
hours more, I again vifited them, and find- 
ing fome of the mixtures in motion, I 
marked down the feveral appearances, ex- 
actly oppofite to each, as may be feen by 
looking into the fecond table, and firfi: co- 
lumn. 
But as I imagined that the natural 
courfe of the fermentation muff have been 
difturbed from the firfi; fetting out, on ac- 
count of the extraordinary heat, I was not 
very folicitous about a minute and accurate 
obfervation of the progrefs; more efpe- 
cially as I intended to take the trouble of 
mixing up an entirely new fet. I there- 
fore did not go near the place where the 
phials ftood for two days, leaving them all 
this while in the cold; but going then to 
examine them, was furprized to find that 
notwithfianding their being unaffifted by 
heat, yet moft of them had fermented, and 
fome of them were ffcill in motion. I there- 
fore minuted down, in the table, the ap- 
pearances particularly belonging to each, as 
they ftand in the fecond column. 
Soon after this time, I engaged in a 
courfe of experiments, with a view of dif- On the Fermentation of 
covering the relative quantity of air, fet 
free from different compounds, and there- 
fore found it unnecelfary to repeat all the 
experiments of the fecond table, as I had 
once intended; but at the end of a fort- 
night I went to the Elaboratory, where the 
phials had been left, and found fome of 
them four, fome putrid, others mufty, and 
fome of the mixtures Hill fweet; but as I 
had not the table with me, did not minute 
them down particularly. 
Now fince it appears, that thefe mix- 
tures ferment fo very readily, even when 
unaffifted by heat, how can there be any 
doubt but they muff run through the fame 
procefs when they are received into the 
warm ftomach, and are put in motion by 
the fermentative power of the faliva ? which 
not only the authorities of Hoffman and 
Boei-baave, but likewife the experiments 
jufl now recited, fhew to be poffelfed of 
this power in a very eminent degree; as 
maybe plainly feen by comparing the num- 
bers i, 3, 5, and 7, of the fecond table, 
with the mixtures numbered 2, 4, 6, and 
8, in the fame table. 
The progrefs of digeftion in the human 
body may be traced in the following manner. Alimentary Mixtures. 
The food, divided by maftication, and 
mixed with the faliva, is fitted for begin- 
ning the intejiine motion very foon after the 
alimentary lubftances are received into the 
ftomach ; this motion being raifed by the 
temperate warmth of the place, by the 
remains of the former meal, and by the 
fermentative power of the faliva and gaf- 
tric juice. The firft effect of this motion, 
is, to throw up to the furface the folid 
part * of the alimentary mixture ; which 
foon again fubfiding, the air which buoyed 
up the folid particles having efcaped, the 
union of thefe is prefently deftroyed, and 
the whble mixed with the digeftive fluids; 
this intimate mixture being much aflifted 
and completed by the agitation caufed by 
the periftaltic motion, by the alternate 
prefiure of the diaphragm and mufcles of 
the abdomen, and by the continual pul- 
* Every perfon muft have perceived, at one time or 
other, that after a hearty meal, if an erudlation fhould 
by any means be excited, fomeof the folid part of what 
had been taken into the ftomach comes back towards 
the mouth. If the meal confiftedof a mixture of ani- 
mal and vegetable food, it is part of the vegetable that 
always rifes; which correfponds exactly with the ap- 
pearances in the phials, where I conftantly obferved the 
vegetable part of the mixture to rife firft. On the Fermentation of 
fation of the neighbouring large blood 
velTels. 
Thus the aliment palfeth on from the 
Jlomach into the duodenum, and through 
the long tra£t of the fmaller intefiines; 
where having its original nature entirely 
changed, by the admixture of the bile and 
pancreatic juice, but chiefy by the fer- 
menting motion, which dill continues go- 
ing on, the feveral kinds of food are all 
blended and mixed together into one mild, 
fweet, and nutritious liquor, now in brifk 
fermentation, called chyle. This chyle *, 
* That the chyle is a liquor in a ftate of actual fer- 
mentation may be proved from obferving the changes 
that happen in milk, which is nothing but chyle, a 
very little animalized. u The acidity which milk na- 
te turally contracts in a few days, muft be confidered 
cc as the effect of a fermenting motion, which difco- 
“ vers in that liquor an acid that was not perceptible 
*c before; this, properly fpeaking, being an acetous 
fermentation, which the milk pafleth through in its 
61 way to putrefaction, which foon follows if it be ex- 
“ pofed to a hot air.” Macquer. 
Hence the reafon why a diet confifting entirely of 
milk is fo apt to create a fournefs in the firft paflages ; 
for being in aftual fermentation when taken into the 
body, if it be not very foon carried through the fmaller 
mteitines, the fecond ftage will come on. And here 
we may perceive the rie’ceffity that there is for the agi- 
tation and exercife of infants at the breaft. Alimentary Mixtures. 
19 
fo compounded, is taken up by millions of 
little abforberit veiTels, fully charged with 
the fubtile, active, antifeptic fpirit, and 
conveyed to the receptacle $ where, and in 
the thoracic duBy it is further mixed with 
great quantities of lymph, and, after no 
very long courfe, is poured into one of the 
large veins, in order to communicate its 
inteftine motion to the blood, to prevent 
the natural tendency of the fluids to pu- 
trefaction, and to repair the wafte which 
our bodies, every moment of our lives* 
mull rieceflarily fuflain. 
THE grofs, infoluble, and fecal parts of 
the aliment being thrown off from fuch as 
were finer and more nutritious, pafs on to 
the larger inteftines ; where, at their very 
firft entrance* they meet with a ftore of 
four and putrid ferments, lodged in the 
ccecimt and appendicula vermiformis, which, 
in a very fhort time, convert the alimen- 
tary remains into their own nature; and 
thus communicate a degree of tharpncfs 
which muft foon ftimulate the inteftines to 
a contraction, that ends in expelling thefe 
ufelefs and oftenfive matters out of the body. 
All this is to be underftod of the di- 
geftive procefs, as carried on in perfons 20 
On the Fermentation of 
who have the happinefs to enjoy a perfectly 
found ftate of health; but in valetudinary 
people, of weak and relaxed habits ; in 
pregnant women, whofe ftomachs, and a 
great fhare of the fmaller inteftines, are 
thru ft out of their natural fituations ; and 
in people whofe inclinations or profefiions 
oblige them to lead fedentary lives ; the 
food is often detained fo long in the firft 
paftages, as to pafs on to the fecond fta-ge 
of alimentary fermentation; and then it 
produceth a moft auftere acid, which how- 
ever is exaCtly in the fame ftate with a fo- 
reign acid, for the la&eals will admit none 
of it : It is therefore of neceflity accumu- 
lated, and proves the caufe of four eructa- 
tions, heartburning, vomiting, griping, or 
loofenefs, according to its quantity, degree 
of ftrength, and place where lodged. 
This four acrimony, when once eftab- 
liihed, is not to be removed without fome 
difficulty ; for fome of it always lying in 
the firft paftages, ferves as a leaven to aCt 
on every thing taken into the ftomach ; 
and thus, hurrying the alimentary mix- 
ture through the firft ftage, and imme- 
diately bringing on the fecond, renders the 
food incapable of furnifhing a nutritious Alimentary Mixtures. 
21 
chyle, as not being thoroughly fermented, 
and alfo wanting a fufticiency of the true 
invigorating fpirit; all which plainly ap- 
pears from the palenefs and languid difpo- 
fltion of thofe people who are much af- 
flicted with a fournefs in the ftomach. 
And hence the reafon why exercife, efpe- 
cially riding, (which agitates the vifcera, 
and prevents the too long flay of the ali- 
ment in the firfl paffages) and the aroma- 
tic gums and bitters, together with chaly- 
beates, (which produce the fame effect, 
by their ftimulating and ftrengthening qua- 
lities) prove fo very ferviceable in all thefe 
cafes. 
But if the aliment, either from its own 
very putrefcent nature, or from its too long 
flay within the confines of the fmaller in- 
teftines, fhould ever proceed on to the 
third ftage of fermentation, it will then 
become fo offenfive as to occafion imme- 
diate efforts to throw it off, if the quan- 
tity of putrid matter be in any degree con- 
fiderable ; but if that fhould not be the 
cafe, it may then remain in the body, and 
gradually infinuate itfelf into the mafs of 
fluids, until it accumulates to fuch a height 
£3 to throw the whole fyflem into a con- On the Fermentation of 
fufion, which mud terminate either in the 
poncoCtion and expullion of the offending 
matter, or in the deftruCtion of the ma- 
chine itfelf: For any thing putrid is to- 
tally incompatible with the perfeCt well- 
being of an animal body; and therefore 
FutrefaBion cannot by any means be ad- 
mitted to a fhare in the procefs which is 
to furnifh this body with nourifhment and 
fupport. 
And here we may remark the admira- 
ble (Economy cf nature, in guarding fo 
effectually againfl this hoftile putrefactive 
principle, by fo ordering the procefs of 
alimentary fermentation, that, of the two 
firft ftages, the one fhould have the pro- 
perty of producing a fpirit of fuch amaz- 
ing activity that it muff pervade the molt 
intimate receffes of the vafcular fyftem ; 
and that the other fiage fhould yield an 
acid, which, if it hath not in itfelf all the 
penetrating power of the antifeptic fpirit, 
ihall yet be enabled to correCt the putre- 
factive tendency of whatfoever it comes 
into contaCt with, and thereby render it 
piild and inoffenfive. 
This fpirit, or vapour, which is fet 
fixe from the mixtures during their fer- Alimentary Mixtures. 
23 
mentation in the firft pahages, which en- 
ters the compofition of the chyle, and with 
that fluid is tranfmitted to the blood, there 
to prevent or correct the putrefactive dia- 
thefis, appears to be chiefly the Fixed Air 
of the alimentary fubftances; but as this 
matter cannot be fully explained, nor tho- 
roughly underftood, without a knowlege 
of the properties of air, when confidered 
as a conffituent principle of bodies, I mult 
referve the further illuftration until it be 
lhewn what thofe properties are. ESSAY II. 
ON THE 
NATURE and PROPERTIES 
O F 
m i a ; 
FIXED AIR. May we not, •tvith good reafion, adopt this 
now fixed, now volatile Proteus, among 
the chymical principles, and that a very 
atlive one ? Hales. ESSAY II. 
# 
O N T H E 
/ 
Nature and Properties of 
Fixed Air. 
THAT great improver of natural 
knowlege, the honourable Mr. Boyle, 
knew from a variety of experiments, “ that 
“ air might be produced from the fer- 
t£ mentation, corrofion, and diflolution of 
“ bodies; by the boiling of water, and 
“ other liquors ; by the mutual actions of 
“ bodies upon one another, efpecially the 
<f faline ones; and, laftly, by the analyling 
and refolving certain fubftances*;” but 
this noble philofopher feems not to have 
known the principal ufe of this air, which 
is fo intimately mixed with, and wrought 
into the compofition of animal, vegetable, 
and mineral bodies. 
* Boyle’s Works, abridged by Shaw, vol.iii. p. 21. 28 
On the Nature and 
It is therefore to the indefatigable in- 
dufixy of the excellent Dr. Hales, that the 
world is indebted for the difeovery that 
this elaftic matter, fo nearly refembling 
common air, is the principle which fonns 
the cement, or bond of union, between the 
feveral conftituent particles. 
But although it is now near forty years 
fince this truly ufeful philofopher publilhed 
the account of his curious experiments, 
and thereby opened a new field in natural 
philofophy, yet the enquiry hath been but 
little profecuted; and, excepting Haller, 
there is no fyftematic writer that I know 
of, either in chemifiry or phyfiology, who 
has given that attention to Dr. Hales s dif- 
coveries which they certainly merit. 
This celebrated phyfiologifi: indeed 
hath fully adopted the lyfiem of Hales, 
and holds air to be the •vinculum elemento- 
rum primarium, the true cement which 
binds together the earthy particles of bo- 
dies 
* Videtur acr vinculum elementorum primariuni 
conftituere, cum non prius ea elementa a fe invicem 
difcedant quam aer expulfus fuerit. Iialleri Elan. Pby- 
fiologia, tom, i. jn capitc prime, Properties of Fixed Air. 
All the other writers, and Gaubius, one 
of the lateft, feem either not to know, or 
not to believe any thing of this theory ; 
fince they make cohelion to depend, alto- 
gether, on the attraction fublifting between 
the particles of elementary earth, exclu- 
five of any other principle. And this very 
celebrated profefTor does not fo much as 
mention air, when he is laying down the 
chemical analyfis of the human body *. 
But it did not occur to thefe gentle- 
men, that if earth were the only caufe of 
cohejwn in bodies, there never could be any 
Gluten prseftat verum moleculis terreis adunandis, 
ut conftat cxemplo calculum, lapidum, aliorum corpo- 
rum durorum. In iis omnibus folvitur tunc demum 
partium vinculum quando acr educitur. Ejufdem Primes 
Linece, fed. 244. 
* In ficca materie terreum prae aliis cohaerentiflimum 
eft, atomorum fuarum in proximos contadus compac- 
tione duritiem daturum vix edomandam nift aliorum 
interventu molliretur. Hoc principium cohsefionis, 
quietis inertiae. Et ipfa glutina, terrae quam conti- 
nent fuam cohaerentiam debent. Gaubii Inflit. Patbalog. 
Med. fed. 142 iff 143. 
But iftnglafs, and other fubftances of the like na-r 
ture, are deprived of the glutinous quality by quick- 
lime ; the reafon of which will be laid before the 
reader in the courfe of thefe Eflays, particularly the 
Fifth.  On the Nature and 
30 
change in their combination: For tc if all 
<c the parts of matter were only endued 
“ with a ftrongly attracting power, whole 
“ nature would then immediately become 
“ one unadtive, cohering lump ; where- 
“ fore it was abfolutely neceftary, in or- 
te der to the actuating and enlivening this 
“ vail mafs of attracting matter, that there 
(t fhould be every where intermixed with 
te it a due proportion of ftrongly repelling 
“ elaftic particles, which might enliven 
<c the whole mafs by the inceftant action 
t( between them and the attracting parti- 
<f cles 
It is plain, therefore, that the principle 
upon which cohefton immediately depends 
muft be of a volatile or fugitive nature, 
not fixed and indeflruttible, like earth ; 
otherwife, the face of this globe would be 
covered with dead bodies ; for when once 
a ftop is put to the life of either animal or 
vegetable, they become no longer ufeful in 
the general fyftem, as organized bodies; 
and it is then abfolutely neceftary that 
their frame fhould be diflolved, and their 
elementary particles difperfed, in order to 
* Hales’s Staticks, vol. i. p. 314. Properties of Fixed Air. 
form nourifhment for thofe beings that yet 
continue to live. 
It will appear hereafter, that the opi- 
nions of Hales and Haller are well ground- 
ed ; and that the principle which is gene- 
rally known by the name of Fixed Air, is 
the immediate caufe of coheflon, flnce the 
prefervation of firmnefs and foundnefs in 
bodies depends on retraining the efcape of 
this air *, for the moment it flies off', and 
refumes its elaflicity, we fhall fee that the 
other constituent particles, the earthy, the 
faline, the oily or infla??mable, and the aque- 
ous, being thereby put in motion, imme- 
diately begin to exert their feveral peculiar 
attractive and repullive powers, and run 
into new combinations, which firft change, 
and at length altogether deftroy, the tex- 
ture of the fubftance they formerly com- 
pofed, provided that this fubftance con- 
tained in itfelf a fufticient quantity of wa- 
ter to allow of the inteftine motion, by- 
giving the proper degree of fluidity * j for 
without fluidity there can be no inteftine 
* Here we are not to underftand abfolute fluidity* 
but only fuch a degree of morfture and foftnefs as will 
allow the feveral conftituent particles to fhift and 
change their places.  On the Nature and 
32 
motion, and without inteftine motion there 
can be no change of combination ; fince 
we fee that fuch animal and vegetable bo- 
dies as are fuddenly deprived of their wa- 
ter, or naturally contain very little, are al- 
moft as durable and unchangeable in their 
textures as minerals. 
That this air, which is alleged to be 
the cementing principle, fhould have the 
property of palling from a repellent, elajlic 
ftate to the oppolite of nonelajlic, and 
Jlrongly attracting, and vice verfa, is not 
eafily comprehended -, nor indeed could it 
be believed, if the number of experiments, 
which prove it, had not put the matter be- 
yond all manner of doubt: So that thefadt 
is as certain as that we breathe air *. 
This, as well as the property of elective 
attraction in the minute particles of mat- 
ter, was not unknown to that amazingly 
comprehenfive genius, Sir Ifaac Newton •f-; 
and it was by purfulng the hint of that 
great man, that Dr. Hales engaged in an 
enquiry which enabled him to eftablifh 
the theory aforementionsd, and which 
* See Hales’s Staticks, vol. i. p. 293, and vol. ii. 
279 y 281. 
t See Newton’s Optics, queft. 30 31. Properties of Fixed Air. 
hath been illuftrated and confirmed, with 
regard to a particular clafs of bodies, by 
the experiments of Dr. Black *. 
But there is ftill a great deal wanting 
to complete the illuflration, which de- 
mands a number of accurate experiments; 
more, perhaps, than will fuit the leifure 
or inclinations of any one perfon, and 
therefore muffc be brought to perfection 
by the united labours of many* 
With this view, I began a fet of ex- 
periments, and refolved to obferve carefully 
the appearances attending the fermenta- 
tion of fuch mixtures as ufually make up 
part of our food, and alfo the appearances 
which attend the putrefaction of animal 
fubftances; hoping from this branch of 
enquiry to obtain further light concerning 
fome points of very great importance in 
the animal ceconomy. 
EXPERIMENT i. 
To try the relative quantity of air, fet 
free from different mixtures by fermenta- 
tion, I put into three phials, marked i, 2, 
and 3,, firfl, the iimple fermentative mix- 
* In his Experiments on Magnefia. 34 
On the Nature and 
ture, about three ounces j fecondly, a like 
quantity of bread and water and the third 
phial had nothing but three ounces of 
common water; thefe two lad being de-. 
figned as dandards. 
The phials, as reprefented at B, (dg. i) 
were placed in a tin pan (A), half full of 
water, on little pededals, and covered over 
■with cylindrical glades (C) of feven inches 
in height, and three in diameter. 
The air was then drawn out of the 
cylindrical glades, by fudtion through a 
fyphon, fo as to raife up the water about 
half way, and then little bits of paper were 
paded on the ddes, to mark the rife of the 
water. 
Every thing being thus ordered, the 
whole apparatus was placed before a dre, 
at fuch a didance as was fudicient to keep 
up a moderate degree of heat. 
As the heat began to operate, the va- 
pour in each of the glades expanded itfelf, 
and forced down the water to a certain depth, 
nearly about half an inch ; but at the end 
of eight hours, when the mixture of bread 
and flefh-meat (No. i) was in brifk fer- 
mentation, the water in its cover was funk 
one third more than in the other two, and Properties of Fixed Air. 
in twelve hours it was double, being then a 
complete inch from the mark. 
During the night, the whole became 
cool the confequence of which was, that 
the expanded vapour in the glafies 2 and 3 
was found in the morning perfe&ly con- 
den fed, the water having returned to its 
original height; while the air that had 
been fet free from the fermenting mixture 
(No. 1) dill maintained its elafticity, keep- 
ing down the water in the cylindrical glafs 
an inch and two tenths. 
The pan was again placed before the 
fire ; and, at fix in the evening, the water 
in the glafs belonging to No. 1 was forced 
down two inches, that in the other two 
half an inch. 
Next morning, the vapour being again, 
condenfed by the cold during the night, 
the water ftood at an inch and a half from 
the mark in the fermenting phial, but in 
the phials No, 2 and 3, it rofe to the marks 
as before. 
I placed the whole again near the fire, 
and the vapour operated as before. On 
the third morning, the water belonging to 
the phial No. 2 had returned as ufual to 
the original heighth; while in the other, 
35 36 
On the Nature and 
No. i, it was flill kept down a full inch 
and half, by the force of the extricated 
air. 
I now threw out the bread and water, 
(from No. 2) and put into the fame phial 
half an ounce of boiled beef cut fmall, and 
two ounces of water; and having placed it 
under the cover, and raifed the water by 
fudtion, as before, I fet it in the pan along 
with the fermented mixture, which by this 
time had entirely ceafed from working. 
After handing fix hours in the warmth, 
no elaftic air appeared to have been fet 
free from the beef, the water being funk 
only half an inch. The other phial (No. 1) 
now flood exactly at an inch and a half, 
which, allowing half an inch for the ex- 
pansion of the vapour, Shewed that the 
mixture had now been for fome time in a 
condition to abforb air, as Dr. Hales 
termed it, for at the fame hour the day 
before the water was down two inches. 
On the 4th morning, when all was cool, 
the fermented mixture was found flill to 
keep down the water near an inch, but in 
the glafs with the beef only the water was 
up to the mark. Properties of Fixed Air. 
From hence, and from other experi- 
ments *, it fhould feem, that animal fub- 
ftances when alone, and the fubftance of 
vegetables when alone, do not part with 
their air without fome reluctance; but 
that when the two are mixed together, un- 
der certain conditions, that then an attrac- 
tion begins, which prefently throws off 
the air that fo clofely adhered to each of 
them in a feparate hate ; and this air, in 
the moment of its extrication, refuming 
its elaflicity, deftroys the union of the mi- 
nute particles, and, producing an intefline 
motion, totally changes the nature of the 
body in which it was fixed, by allowing a 
new difpofition and a different combina- 
tion, to take place. 
And in this manner is brought about 
the perpetual tranfmutation of animal and 
vegetable bodies, whereby they mutually 
afford nourifhmeut to each other. 
It has appeared that the alimentary 
mixtures, though at firft they throw off a 
confiderable quantity of elaflic air, yet, 
* See No. i of the firft table ; and No, r, 3,5, and 
7, of the fecond table ; and compare them with thofe 
{mixtures that had either flefti or faliva. On the Nature and 
after fome time, they abforb this air, and 
again reduce it to a non-elafiic ftate. 
As the fermentation in the ftomach muft 
begin very foon after the aliment is re- 
ceived into it, we may reafonably conclude, 
that the alimentary mixture will alfo begin 
to abforb much fooner in the bowels than 
it appeared to do in the phial ; and thus 
the elaftic air, which is fet free from the 
food, will, in great meafure, return to a 
hxt, or non-elaftic ftate, before the chyle 
enters the ladfeals 
* 44 Since we find fuch great quantities of elaftic air 
44 generated in the folution of animal and vegetable 
?c fubftanccs, it muft needs be, that a good deal does 
44 conftantly arife from the diftolving of the aliments 
44 in the ftomach and bowels, which difiolution it 
44 greatly promotes j fome of which may, very proba- 
44 bly, be reforbed again by the fumes which arife 
44 with them. Thus we fee, that the variety of 
44 mixtures in the ftomach appear fometimes to gene- 
?c rate, and fometimes to abforb air. In a true kindly 
digeftion, the generating power exceeds the abforb- 
f4 ing power but a little 3 but whenever the digeftion 
c4' deviates in fome degree from this natural ftate, to 
fc generate a greater proportion of elaftic air, then are 
44 we troubled more or lefs with diftending flatufes.” 
Hales's Stat. vol. i. p. 309. Properties of Fixed Air. 
It has been imagined by a very inge- 
nious gentleman j'*, that the alimentary 
fubflances carry their fixed air into the 
blood, without its ever having been extri- 
cated, or thrown off into an elaflic flate, 
during digeftion ; but this is to fuppofe, 
that thefe fubflances are never thoroughly 
broken, nor fuffer any change of combina- 
tion, from the adlion of the digeflive or- 
gans ; a fuppofition which cannot by any 
means be allowed; it being demonjirable 
(as I humbly apprehend) that the food is 
intirely broken, and its original nature to- 
tally changed, while it is palling through 
the alimentary canal. 
39 
EXPERIMENT 2. 
Into the fame three phials which were 
made ufe of in the foregoing experiment I 
put, firft, the Ample fermentative mixture; 
2, the fame, with one third frefh lemon- 
juice ; 3, the fame, with one third claret. 
* Dr. Black. In his Differ t alio Med. Inaug. De Hu- 
more acido a Cibis or to, he is fo far from believing that 
the aliment naturally ferments in the ftomach, that he 
looks on fuch fermentation, when it does happen, to 
be the caufe of many, and thofe very dangerous dif- 
eafes. See p. 8 and 9 of the Thefts above-mentioned. 40 
On the Nature and 
The phials were all placed in the pan as 
before, and the water drawn out by fudtion. 
The phial, No. 1, prefently began the 
motion, the folid part all rifing to the top; 
and as it fermented, I found that more air 
was extricated than there had been from 
No. 1 of the preceding experiment, which 
I afcribed to the tendernefs of the mutton 
which was ufed in this prefent mixture, 
as having been longer kept than fome 
beef that I had mixed up for the former 
trial. 
No. 3, with the claret, did not begin to 
move until it had flood 24 hours; and No. 
2, with the lemon-juice, after remaining 
thirty-fix hours, fhewed no figns of mo- 
tion at all; fo that here the proportion of 
lemon-juice was too great; and it appears 
to have adted as a pure acid, which, as 
well as fermented liquors, we find retrains 
the alimentary fermentation. 
EXPERIMENT 3. 
At the end of thirty-fix hours, I threw 
out thefe mixtures, and filled the phials 
again, with, 1, the fimple fermentative 
mixture, and an ounce of green herbs; 
('viz, onions, water-crefles, and garden Properties of Fixed Air. 
crelfes, aa p. <z.) 2. The fermentative 
mixture, with an ounce of lemon-juice and 
half an ounce offaliva; 3. The mixture, 
with two drachms of very itrong rum. 
The mixture, No. 2, with the lemon- 
juice and faliva, began to ferment imme- 
diately ; and, before two hours were ex- 
pired, all the folid ingredients had rifen; 
No. 1 began foon after; but it was not till 
after ten hours, that the mixture with the 
rum fhewed any figns of motion. 
Here we have another ilrong inilance 
of the fermentative power of the faliva, 
which being compared with thofe in the 
fecond table, plainly iliew that Boerhaave 
and Hoffman were both in the right, when 
they afcribed this quality to it. 
When the mixture with the lemon- 
juice had ceafed from working, I dropt 
Lixivium Lartari into fome of the liquor, 
but not the lead ebullition enfued, which 
ihews, how intirely the fermentatory mo- 
tion changes the nature of thefubilance fer- 
mented ; for here wras one third of this 
mixture, a iharp acid liquor, which would 
have effervefced violently before the fer- 
mentation began ; and hence we may con- 
clude, that acids, even independant of  On the Nature and 
their mixture and dilution by the native 
animal juices, mufl be neutralized by the 
mere force of fermentation in the firft paf- 
fages, if the digeftion proceeds as it ought 
to do. 
In the mixture with the herbs, the fmell 
of the onion was Rill very ftrong, even af- 
ter the fermentation was over; which 
agrees with what every body muft have 
perceived, with regard to the fermentation 
of things of this fort in the ftomach ; fome 
of this tribe, fuch as garlick, retain their 
peculiar fmell, even after they have under- 
gone fo much of the addon of the body, as 
to become perfpirable matter. 
Although the mixture with the rum 
was the lateffc in beginning, yet, after the 
motion began, it was more brifk, and 
hniihed its career fooner, than either of 
the other two phials; but not above half 
the quantity of air was extricated that there 
was from the fimple mixture, No. 1, of 
the foregoing experiment. 
EXPERIMENT 4. 
Two of the phials were placed in the 
pan and covered with the glades; one hav- 
ing two ounces of a caudle, made of oaten Properties of Fixtd Air. 
gruel, Lifbon white-wine, and fugar, with 
a little lemon-juice ; and the other, the 
fame quantity of the caudle, and two 
drachms of faliva. 
The phial which had the faliva, began 
the fermentatory motion immediately, but 
it never became brilk, and in about 14 
hours intirely ceafed; a fmall quantity of 
air was extricated at firft, but the mixture 
foon went on to the abforbent Rate, for by 
the time that the fermentation had ceafed, 
the water in the • cylindrical glafs was 
raifed half an inch above the mark. 
The other phial without the faliva never 
fhewed any figns of motion. 
Hence we fee the reafon, why this fort 
of caudle lits fo light with people whofe 
bowels are apt to give too much way to 
diftending flatus fuch as lying-in women, 
and perfons in feverifh diforders. 
EXPERIMENT 5. 
I filled the three phials, i, with juice of 
turneps alone; 2, the fame juice, with 
two drachms offaliva-, and, 3, bread and 
water, with two drachms of faliva, and as 
much fpirit of vitriol as gave the mixture a 
confiderable degree of fharpnefs, and made 44 
On the Nature and 
it efFervefce fmartly upon dropping in oil of 
tartar. 
The phial, No. 2, with the faliva, be- 
gan to fhew figns of motion immediately; 
and, in five or fix hours, the fimple tur- 
nep juice was likewife in motion, and 
both the one and the other fermented very 
brifldy. 
But No. 3, though it fhewed figns of 
motion very early, never became brifk ; fo 
much had the acid deflroyed the fermenta- 
tive power of the faliva. However, what 
little motion it did undergo, fo far altered 
the date of the acid, that it would not ef- 
fervefce, upon adding the fixed alkali. 
EXPERIMENT 6. 
Into one of the phials I put three 
ounpes of the fimple fermentative mixture, 
and a drachm of the cortex in powder ; into 
the fecond phial I put the fame quantity of 
the mixture, and a drachm of carraway- 
feeds in powder ; the third had nothing but 
three ounces of the mixture, fo ferve as a 
Handard to the other two. 
The phial with the bark began to fhew 
figns of motion as foon as it became warm, 
and the other, with the feeds, in two Properties of Fixed Air. 
hours after; the Ample mixture was not in 
motion till three hours later. 
The cortex fermented very brifkly, as 
did alfo the carraway-feeds; but there was 
at leaff one half more air extricated from 
the latter than from the former, which 
fhews that many of the carminatives may 
generate air in the bowels, as well as ex- 
pel it: And if thefe things were given in 
large dofes, we might account for their 
adtion, by faying, that it is the fudden 
extrication of their air which ftimulates 
the mufcular coat of the flomach, and ena- 
bles it to throw off" the offending flatus. 
But as they are always given, and in- 
deed can only be taken in ffnall quanti- 
ties, it is upon the hot oil with which 
thefe aromatic fubftances abound, that 
their carminative virtue depends; for we 
fee that ardent fpirits, which neither con- 
tain much air themfelves *, nor facilitate 
the extrication thereof from any thing 
they are mixed with, are yet very power- 
ful carminatives, which muff therefore be 
owing folely to their power as flimulants. 
* “ I found very little air in 54 cubick inches of 
(t brandy.” Hales's Stat. vol, i. p. 181. 46 
On the Nature and 
EXPERIMENT 7. 
I had, on a former occafion, made up 
mixtures with fugar, wort, and honey, but 
as the progrefs of that experiment was in- 
terrupted, I refolved to repeat it. 
Three mixtures were made accordingly: 
1. Of boiled mutton (without any bread) 
5fs, water 5ij, and frefh wort, or infulion 
of malt, §ij. 
2. The fame quantity of mutton and 
water, with two ounces of a Rrong folu- 
tion of brown fugar (about four to one). 
3. The like quantity of mutton and 
water, with two ounces of Rrong folution 
of honey. 
These phials were not placed in the 
pan, as in the foregoing experiments, but 
Hood in a fand bath, heated by a lamp. 
The mixture, No. 1, with the wort, 
was the firft that began the fermentatory 
motion, and that very early, in lefs than 
an hour after the phial became warm; the 
fugar began next, about two hours later; 
but the honey was not in motion until it 
had Hood above eight hours. 
I frequently fhook all thefe mix- 
tures, and found the fermentation greatly 
accelerated thereby. Properties of Fixed Air. 
47 
Thus it appears, that honey is not fo 
fermentable, when mixed with animal 
fubltances, as fugar ; nor fugar fo prone 
to fermentation as the common infuiion of 
malt; and perhaps thofe difturbances in 
the bowels, which are often obferved in 
people of delicate and very irritable conlti- 
tutions, after the ufe of honey, are occa- 
lioned by this refractory quality, fmce it 
may lie a conliderable time undifl'olved in 
the Itomach, and there aCt as a {Emulating 
fait. 
Upon the fame principle, this may 
guide us in directing fugar and honey in 
the diet of fick perfons : Where the na- 
ture of a difeafe requires a diet of the molt 
eafily fermentable kind, fugar mult be 
preferable to honey; unlefs fomewhat of 
a laxative nature be likewife demanded, 
when honey, unlefs the patient has a pe- 
culiar dillike to it, will have the advan- 
tage. 
EXPERIMENT 8. 
While thefe mixtures were in fermen- 
tation, I fufpended a little thin bit of very 
putrid mutton in the neck of the phial 
with the wort, and left it there during the 48 
night; in the morning it was found to 
have lofl the putrid flench, having now no 
fmell but that of the mixture. 
On the Nature and 
EXPERIMENT 9. 
I also fixed one extremity of a bended 
glafs tube into the neck of the phial with 
the fugar, and the other into a little bot- 
tle containing a drachm, or thereabouts, 
of the fpirit of fal ammoniac made with 
quick-lime, (as reprefented in the third 
figure). After they had remained in this 
fituation twenty-four hours, I feparated 
the phials, and dropping in lpirit of vitriol 
on the volatile alkali, found it effervefce 
very fmartly. 
Afterwards, I transferred the air 
from a fimple fermenting mixture fi. e. 
Bread, flefh meat, and water) into the fame 
cauftic volatile alkali; as I did likewife 
from melafles wadi * in fermentation, and 
from a mixture of cortex and putrid bile, 
which fermented brifkly, and fweetened 
* Melafles walh, as it is termed by the diftillers, is 
a liquor brewed from melafles and water, and after- 
wards fermented by the means of yeafl:; in order to di- 
ftil, and make what are ufually called fugar-hcufe 
fpirits. Properties of Fixed Air. 
the putrid gall, all with equal fuccefs; in 
every one of thefe instances the fpirit of 
fal ammoniac efFervefcing very fmartly, after 
having been fupplied with air from the 
fubffances in fermentation. 
Which (hews, that the air fet free dur- 
ing the fermentatory procefs, although it 
refumes its elaflicity immediately upon be- 
ing thrown off, is yet capable of return- 
ing inflantly to a fixed flate, provided it 
meets with any fubflance greedy of . air, 
and which hath a power to receive it. 
But here I find that I have been pro- 
ceeding rather too faff, unlefs the reader 
fhould happen to be perfectly well ac- 
quainted with Dr. Black’s very ingenious 
paper on the magnejia: if he is, I fhall 
be underflood; if not, I fhall appear to 
have talked in a language altogether unin- 
telligible. 
Jt is fufficiently known, that the *uola~ 
tile alcaline fpirits, when made by the ad- 
mixture of quick-lime in the difcillation, 
(which they for the mofl part are, in or- 
der to render them more pungent) do not 
effervefce upon the addition of an acid; 
and that no fait, in a concrete form, ever  On the Nature and 
50 
rifes with the phlegm when the procefs iai 
carried on in this manner. 
But it was never well underdood what 
occafioned thefe peculiarities, until Dr. 
Black publidied his experiments. 
That gentleman has {hewn very plain- 
ly, that calcareous earths have a drong de- 
gree of affinity with fixed air, and that in 
their natural date they abound with it; 
that by calcination they are deprived of their 
air; and that it is on account of this de- 
privation that they acquire fo great a de- 
gree of caufiicity, and become fioluble in 
water; and that, on the other hand, this 
caudicity is dedroyed, and the quick-lime 
rendered mild, and infioluble, by refioring its 
fixed air. 
Quick-lime, therefore, when joined 
with fal ammoniac,. in order to make the 
volatile fpirit, not only detains the acid, 
but likewife the fixed air of the crude fait, 
and thus differs nothing but the volatile 
alcali to rife along with the phlegm in the 
didillation. This fpirit, fo raifed, having 
no fixed air in its compodtion, cannot ef- 
fervefee upon the addition of an acid; for 
cfFervefce-nce is nothing more than the Properties of Fixed Air. 
fixed air of the mixture flying off, and re- 
fuming its elafticity, while the acid and 
alcaline particles are rufhing into clofe 
union ** neither can the faline particles of 
the volatile fpirit run together, and form 
chryftals, becaufe air is the bond of union 
in falts -f. 
NE UMA N imagined, that <c perhaps 
“ the quick-lime abforbs, and detains the 
“ earthy matter, which is the bafis of the 
“ volatile fait, and on which its folid form 
“ and its effervefcence with acids depend. 
“ And he relates, that on keeping fpirit 
“ of fal ammoniac, made with quick-lime, 
“ for ten years, it loft almoft all its vola- 
“ tility and fubtility, and in this ftate ef- 
“ fervefeed ifrongly J.” 
But there is not the leaf! occafion for 
waiting fo long to produce this change in 
the nature of the cauftic volatile alcali, 
fince it may at any time be brought about 
in ten minutes by transferring the air from 
fome other fubftance into the non-effer- 
vefeent fpirit* as any one may eafily fatisfy 
* Vide Boerhaav. Element. Chernies, tom. i. p. S31) & 
iom. ii. p. 398. 
+ Hales's Stat. vol. i. p. 298. 
$ Neuman's Chemijlry by Lewis, p.223.  On the Nature and 
himfelf by the following exceedingly pretty 
and conclufive experiment, which is the 
contrivance of Dr. Black, and communi- 
cated by him to my very ingenious friend 
Dr. Francis Hut chef on, le Barer of chemijlry 
in the univerfity of Dublin. 
Put a fmall quantity of the volatile 
fpirit made with quick-lime into the little 
phial marked A, in figure 2, and fix 
clofely into its neck, fo as that no air may 
efcape, one leg of the bended glafs tube 
(B), and infert the other, and likewife 
lute it well, into the mouth of a larger 
phial (C), into which fome alcaline fait 
hath been previoufly put. This phial mud 
have a little hole drilled in the upper part 
of it, as at D, that through this aperture, 
and by means of the fmall glafs funnel (E) 
an acid may be gradually dropt in. 
Things being thus fixed, pour in fpirit 
of vitriol, or any other acid, that an ef- 
fervefcence may enfue; and while that is 
going on, the little hole (at D) is to be 
llopt occafionally, in order to force over 
the extricated air into the phial A. An 
ounce of alcaline fait * expended in this 
* Potajb is the alcali which I generally make life of 
for this experiment, oil account of its cheapnefs. Properties of Fixed Air. 
53 
manner will ferve to fupply a like quantity 
of cauflic alcaline fpirit with a fufficiency 
of air to make it effervefce very fmartly, 
when the phials are feparated, and an acid 
dropt into the one which contains the (be- 
fore) ?ion-ejf'ervefcent fpirit. 
EXPERIMENT io. 
Many of the preceding experiments 
have (hewn, in the ftrongeft light, the 
fermentative power of the faliva : I de- 
termined, however, to try it once more, 
and to compare it with the bile, in regard 
to this quality. 
I therefore mixed an ounce and half 
•of bread and water, beat up thin, with 
half an ounce of faliva j and the fame 
quantity of bread and water, with half an 
ounce of ox-galL 
The firft mixture fhewed ligns of mo- 
tion from the very beginning, and, in lefs 
than an hour after it became warm, the 
motion was bri/k the fecond, with the 
gall, was not fo foon in motion, it being 
three hours before the bread had all fairly 
rifen to the furface ; but the fermentation 
continued twice as long, and the motion 54 
On the Nature and 
was more brifk than in the mixture with 
the falha. 
And thus it appears very plain that the 
bile has a power, like other animal fluids, 
to raife a fermentation, when mixed with 
vegetable fubflances. 
EXPERIMENT 11. 
Two drachms of boiled mutton, per- 
fectly fvveet, were beat up with an ounce 
of water, and put into one phial ; the 
fame quantity of the mutton beat up with 
Jialf an ounce of faliva, and as much wa- 
ter, were put into another phial ; and 
both of them left in the common tempe- 
rature of the air, which was cool for the 
feafon (beginning of June), the thermo- 
meter being at 60. 
In thirty-fix hours, the contents of the 
firfb phial became putrid; the other, which 
had the faliva, remained fweet for forty- 
eight hours; but both of them fermented; 
that is to fay, an inteftine motion took 
place, the folid part all rofe to the furface, 
and bubbles of air repeatedly formed, and 
continued difcharging themfelves, for fe- 
yeral hours before any putrid fmell wa§ 
perceivable. Properties of Fixed Air. 
55 
EXPERIMENT 12. 
A drachm of boiled mutton, perfectly 
fvveet, beat up with an ounce of water, 
was put into one phial; the fame mix- 
ture wras put into another, and a bit of 
thread being dipt in fome putrid liquor 
which lay about rotten beef,' about the 
tenth part of an inch of this thread was 
cut off, and thrown into the phial. 
In twenty-four hours, the contents of 
the fecond phial, after undergoing the in- 
tefline motion, were found putrid; the firft 
did not betray the leaf! putrid fmell until 
it had flood twelve hours longer. 
I repeated this with bile, and found 
the phial into which I had put the bit of 
putrid thread began to fmell feveral hours 
fooner than the other, which contained bile 
and water only. 
These experiments confirm the eight- 
teen th of Dr. Pringle s, and plainly fhew, 
that bodies in a Rate of putrefaction are 
exciting ferments to fuch as are fweet. 
EXPERIMENT 13. 
It has appeared from the 6th of thefe 
'experiments, that the cortex ferments very 56 
On the Nature and 
readily when joined with a mixture of ani- 
mal and vegetable matters, and even feems 
to promote that fermentation; but I was 
defirous to khow how it would operate 
wrhen joined only to the falfaa. 
With this view, I mixed up a drachm 
of the bark in powder, with half an ounce 
of jaliva, and as much water. At firSt, 
there did appear fome ligns of motion, but 
they prefently went off, and at the end of 
eighteen hours I found the mixture per-, 
fedtly at red, notwithstanding it had Stood 
the firSt fix hours of this time in a mode- 
rate degree of heat; for the laSt twelve, 
indeed, it had been differed to cool. 
I now added half an ounce of ox-gall-y 
but no motion enfued till twenty hours 
more were elapfed : Then I found the fo- 
Jid part getting up to the furface, and the 
air-bubbles collecting and difcharging; but 
it is to be oblerved that the phial, all this 
while, remained in the cold. 
Finding the motion begun, I placed 
the mixture in a moderate degree of heat, 
and then the fermentation became ex- 
tremely briSk, and continued fo for twen- 
ty-four hours, throwing off great quanti- 
ties of air 5 after which it ceafed, owing, Properties of Fixed Air. 
as I conjectured, to the frequent agitation 
of the phial, which, as hath been before 
obferved, confiderably haftens and fhortens 
the periods of this kind of fermentation. 
Since this moft valuable drug ferments 
in this manner, when fo little aflifted by 
heat, we may fafely conclude that it will 
ferment with very great eafe, when lying 
in the warm ftomach, foftened and opened 
by the diflolvent power of the digeftive 
fluids; and, as will hereafter appear, there 
is good reafon to believe that great part 
of its medicinal virtues depend on this fer- 
mentative quality. 
EXPERIMENT 14. 
In order to clofe this feries of experi- 
ments, I thought it would not be impro- 
per to try the feveral common fartnacea, 
and to compare them with each other, in 
regard to their refpeCtive fermentative 
qualities ; as this might be of ufe in de- 
termining which of them are eafieft of 
digeftion. 
Having made up four mixtures, of 
wheat, barley, oats, and rice, all previoufly 
freed from their outward fhells or hufks, 
and well boiled, fo as to buril the grain,  On the Nature and 
and beat up with the ufual proportion of 
water and flefh meat *, they were then fe- 
veraily put into phials, and placed in a 
moderate degree of heat, about twelve 
hours after they were firft mixed. 
It was not eafy to fay whether the rice 
or the barley began firft, for both of them 
were in brifk motion by the time that they 
had ftood an hour in the warmth 3 the 
mixture with the oats was not in motion 
till about four hours after it became warm, 
and the one with the wheat was three or 
four hours later than it. 
They all fermented very brifidy, and 
being often .agitated, ran through their firft 
ftage in about forty-eight hours. 
Thus we may infer, that crude barley-f- 
and rice will prove light and eafily digefti- 
ble food3 oats next to them3 and wheat 
the moft ftubborn and indigeftible of all. 
But at the fame time we fee, that this pro- 
perty in wheat renders it by much the 
fitteft of all the farinacea for the making 
of bread 3 as it appears tp have firmnefs 
* Boiled veal was ufed in this experiment. 
•j The barley here ufed was what is commonly termed 
pearl-barley. 
Sufficient Properties of Fixed Air. 
fufficient to enable it to bear fome degree 
of fermentation in the baking, and yet re- 
tain enough of its fubftance to undergo 
the alimentary fermentation afterwards in 
the body. 
By this time I had fufficiently fatisfied 
myfelf with refpedt to the manner in which 
digellion is carried on in the human body; 
being now fully convinced that it is neither 
more nor lefs than a true fermentatory pro- 
cefs: For fince all mixtures of animal and 
vegetable fubftances, if furnifhed with the 
requiflte quantity of water, and kept in 
the proper degree of heat *, naturally and 
fpontaneoufly run into fermentation, with- 
out the afliftance of any exciting ferment, 
how is it poflible but that the fame kind 
of mixtures muft ferment in the body, 
when at their very firft entrance they meet 
with a fluid, which, even if their own 
natures were averfe from fermentation, 
would immediately bring it on ? And as 
they pafs farther on, into the Jiomach and 
duodenum, they ftill meet with more fluids, 
endued with the fame power, in an equal, 
* Even heat, we find, is not always neceflary ; fo 
prone are many of this fort of mixtures to ferment. 60 
On the Nature and 
or perhaps fuperior degree: Can it be ima- 
gined then, that thefe fubftances, when 
fo circumftanced, will not undergo the 
changes natural to them ? and that a fer- 
menting motion will not inftantly com- 
mence, and continue fo long as they re- 
main in a place where they are free to ad, 
uninfluenced by any more powerful fer- 
ment j that is to fay, fo long as they re- 
main within the confines of the fmaller 
intejlines ? But foon after the valve of the 
colon is pafied, and that the alimentary 
mixture, which as yet is only in its firft 
flage, comes into con tad: with the acido- 
■putrefattive contents of the larger intef- 
tines, then is its fweetnefs deflroyed, and it 
proceeds on to the fecond and third ftages, 
and thereby acquires a degree of fharpnefs 
and corruption *, which is now become as 
necefifary as it was that the fweetnefs fhould 
continue while the food remained in the 
firfi pafiages. 
* It is to be obferved, however, that the putrefac- 
tion of the faces alvina is of a peculiar kind j and is 
never, excepting in fome morbid cafes, fo complete as 
to furnifli a volatile alcali, on being committed to diftil- 
Iation. Properties of Fixed Air. 
EXPERIMENT 15. 
A drachm of fal-t of wormwood be- 
ing put into one of the cylindrical glades 
defcribed in page 34, and which was ufed 
to cover the phials, and an ounce, or there- 
abouts, of juice of lemons, being poured 
on the fait, the mouth of the glafs was 
llopt, while the ebullition continued, in 
order to confine the air which was extri- 
cated from the mixture. 
When the efFervefcence ceafed, -a live 
fparraw was thrown into the glafs, and in 
lefs than half a minute expired. 
Thus we lee, that the air which is ex- 
tricated from bodies by efFervefcence, as 
well as that which is fet free in the firfi: 
Rage of fermentation, and conftitutes the 
gas fylveftre, hath the deleterious quality of 
fuffocating animals. 
But fal abfynthii, and fa ecus limonum, 
are often given during the aft of ebullition, 
and, I believe there can be no inftance 
fhewn of any perfon’s being deft royed by it, 
notwithftanding what we have juft now 
feen in regard to the fp'arrow which was fuf- 
focated by the vapour arifing from fuch a 
mixture; therefore, the adtion of this ex- 62 
On the Nature and 
tricated or factitious air is very different/ 
when applied direffily to the lungs, and when 
pent up in the bowels of a living animal. 
The fear which thz phyfiologifls conceiv- 
ed of this deleterious quality in the fubtile 
gas, and their not well knowing how to 
difpofe of the great quantities of air which 
mult necelfarily be thrown off, if the aliment 
were fuppofed to ferment, feem to have 
been the chief obflacles that prevented them 
from embracing the doCtrine of alimentary 
fermentation. 
But it feems now proved, that we have 
nothing to apprehend with regard to the 
firftand in refpeCt of the latter objection, 
the experiments above-recited, particularly 
the 8th, 9th, and 10th, plainly fhew, that 
the air which is fet free, either from a fer- 
menting, or from an effervefcejit mixture, 
although it be at firft truly elaftic, yet is of 
fuch a furprizing nature as to be capable 
of returning to a fixed, or non-elafiic fiate, 
the moment it meets with any abforbent 
body that has power to receive it. 
And if we confider that this air which 
is extricated from the food * has the whole 
* Sed is etiam aer, qui prlnceps gluten ejl partium fo- 
il darum animalium, emergit ex intimis, elementa reliiv- Properties of Fixed Air. 
extent of the alimentary canal to fpread 
and diffufe itfelf through, we fhall find 
that it never can create any uneafinefs *, 
excepting when fome acrimonious matter, 
or other ftimulus, though more remote, 
(as in iff eric, hyjieric, and nephritic cafes) 
occafions a fpaimodic conftridtion in fome 
part of the tube, and prevents thereby the 
free and equable diffufion of the elaftic 
vapour. 
quit abfque vinculo. Idem libcratus, diftendit ventri- 
culum magis quam cibi moles. Halleri Prim. Lin. fe£l, 
632. 
* In habits where the whole fyftem of folids is too 
much relaxed, whether from intemperance, profufe 
evacuations, or previous difeafe, the mufcular fibres of 
the ftomach are apt to yield too freely to the elaftic va- 
pour, which is thrown off in the commencement of 
the digeftive procefs, which muft neceffarily bring on 
immediate diftrefs, from the over-diftenfion thus cre- 
ated ; but the parties thus afflidted generally have re- 
courfe to a fpeedy, though otherwife dangerous, re- 
medy, fpirituous liquors : Drams, when fwallowed 
foon after the meal, not only encreafe the mufcular 
power of the ftomach, but alfo retard the alimentary 
fermentation, and thereby give time, before it be far 
advanced, or that much air is fet free, for the food to 
pafs on into the inteftines, where the elaftic vapour 
having fo much more room to diftufe itfelf, no uneafi- 
nefs or oppreflion will enfue. 64 
On the Nature and 
On the contrary, the ufual, natural, and 
gentle degree of diftenfion is of the great- 
eft importance to the animal ceconomy; 
for it ftimulates the mufcular coats of the 
ftomach and inteftines, and thereby excites, 
and keeps up, their periftaltic motion, and 
enables the lafteal, and other minute vef- 
fels, to abforb freely; neither of which 
(the motion nor abforption) could be well 
carried on, if the fides of this long canal 
had been fuffered to collapfe. 
Then, fo much of it as is left unab- 
forbed (for we have feen that the ferment- 
ing mixtures, after a pertain time, rel&rb 
the air, which at firft flies off in an elaftic 
ftate), entering the compofition of the 
chyle *, it ftimulates the veffels appropri- 
ated to the carrying of that liquor, and 
promoting their ofcillatory motion, enables 
them to pour their contents, in a very 
fhort fpace of time, into the general mafs 
of blood. 
* It is not by any means intended here to inculcate, 
that bubbles of air pafs with the chyle into the lac- 
teals. What is meant is, that fome portion of the air 
which enters the compofition of the chyle, is ftill in an 
active, repellent ftate, and that all the vapour which 
was thrown off during the fermentation of the food is 
not as yet deprived of its elafticity. Properties of Fixed Air. 
65 
Here the inteftine motion is communi- 
cated by this adiive principle, the elaftic 
air) while every moment it meets with 
new powers *, which reduce the requifite 
proportion to a nonelafiic Jiate, and leave 
the remainder in poflefiion of its elafticity; 
which is necelTary, to maintain the in- 
tefline motion, and to ferve as a counter- 
poife to the preffure of the atmofphere. 
I am well aware, that this affection con- 
cerning e/ajlic air in animal fluids is di- 
redtly contrary to the do&rine. of Boer- 
haave, who, in exprefs terms, condemns 
the theory of Borelli, in relation to this 
matter. 
* This is afcribed, by Dr. Hales, to the fulphur 
which is in bodies j and he feems to have been led into 
this opinion from obferving, that the fumes of common 
fulphur have a prodigious power to abforb and deftroy 
the elafticity of air. 
But whether it be in reality the fulphur-principle, or 
phlogifton, as it is now more generally termed, that 
has the property of fixing, and reducing to a ftate of 
non-elafticity, this air, which we find is thrown off 
from bodies while they are refolving into their feveral 
component parts, cannot poflibly be determined from 
any difcovery hitherto made. See Hales's Stat. vol. ii. 
p. 108. 66 
On the Nature and 
That great man taught, that the air 
which is found in bodies of all kinds, and 
particularly in animal fluids, is there in 
fuch a ftate as to be altogether incapable of 
acting as air: He thought, that it was di- 
vided into fuch extremely minute parts, 
that its particles were JoUtary, and that, 
while they remained in this divided and fo- 
litary ftate, they had no power to exert 
any of the properties of air $ but that when 
two of thefe particles came within the 
fphere of each others aCtion, then they ac- 
quired the reputfive power, and became 
elajiic and being joined by a third, a 
fourth particle, and fo on, they then burft 
forth in the form of genuine bubbles of 
air. 
But as thefe particles are kept in their 
folitary ftate by the weight and compreffion 
of furrounding matter, or by the preflure 
of the atmofphere, and as they never break 
loofe but when the texture of bodies is de- 
ftroyed, by fire, effervefcence, fermenta- 
tion, or putrefaction or by removing, al- 
moft entirely, the weight of the atmof- 
phere, he contended, that the air in ani- 
mal fluids, fhould not be regarded as air; 
neither fhould we expeCt it to exert any of Properties of Fixed Air. 
its ufual properties3 feeing that, while life 
continues, no fuch changes as thofe above 
ipecified, ever do happen*. 
But Hoffman and Dr* Hales are as expli-* 
cit on the other fide of this argument 3 and 
fbme of the experiments of the latter fully 
authorize him to be fo. His opinion is* 
if that there is a confiderable quantity of 
“ air in vegetables upon the wing, and in 
“ a very active ftate 3” and that this elaftic 
air invigorates the juices of both animals 
and vegetables* while it continues in this 
Hate of activity -f\ 
Indeed there appears to be an abfolute 
necefiity for admitting the exiftence of 
elajlic repellent air, in animal, as well as ve- 
getable fluids 3 for, without it, it feems im- 
pofiible to comprehend how the inteflind. 
* Quin et raturri eft, aera latentem in liquoribus* 
non habere illas vires phyficas quas poffidet dum extra 
liquofes unitus exiftit. Igitur in chylo, lade, Sic. adeft: 
aer naturaliter, fed ita diflolutus, atque proinde tandiu 
non agens ut aer. Boerhaav, Elem. Chernies, tom. i. p. 
519,524,525. Corroll. 6, 7, & 8. Vide quoque Pra-* 
let? i ones Academicas, tom. ii, p. 199. 
f See the Experiments in the third chapter of the 
firft volume of the Staticks 3 and alfo p.216, 315, of 
the fame volume*  On the Nature and 
jnotion can be kept up, or how the canals 
can be preferved in a conftant ftate of per- 
meability : for as all thefe canals are more 
or lefs flexible, and fubjed to the preflure 
of the atmofphere, which is in a perpetual 
courfe of variation, if there were not a 
quantity of elajiic matter mixed with the 
fluids contained in them, to ferve as a 
counterpoife to the external air, an entire 
flop muft be put to their circulation; or 
were this internal air in an unvariable ftate, 
with regard to elafticity, and were it not 
upon every occaflon to preferve the fame 
tenour with the external air, the fldes of the 
canals muft frequently burft afunder. Since 
even the common changes of the atmof- 
phere, in its ufual variation, within the 
compafs of three inches of the barometer, 
would make fuch an alteration of preflure 
as no living body could endure *. 
But when we are told, that the atmof- 
phere is fo light on the tops of exceedingly 
high mountains, that it is fcarce able to 
fuftain a column of mercury of fixteen 
* This difference is calculated by Dr. TVainewright 
to amount to more than a ton and a half (3982 l pounds 
Troy weight. Properties of Fixed Air. 
inches*; and fo heavy in the bottom of 
deep mines, that it can fupport a column 
of thirty inches} and when we know from 
experience, that a man may afcend in the 
one cafe, and defcend in the other, and yet 
feel no great inconvenience, we may be 
certain that the elajiicity of the air in his 
fluids diminifheth, or increafeth, in the 
very fame proportion that the weight of 
the air which furrounds him doth diminifh 
or increafe 5 the elafticity of air being al- 
ways found equal to its denfity. 
And had not an equilibrium been kept 
up in this manner, the velfels muff: have 
burft, in both cafes : In the firft, becaufe 
of the expanfive force of the air contained 
* <£ Le Mercure qui fe foutenoit dans Ie vuide au 
*c bord de la mer, a 28 pouces 1 ligne, fe foutenoit en. 
“ haut, environ 1 ligne au deffous de 16 pouces: les 
elafticites de l’air, s’y trouverent encore exadlement 
“ proportionelles a fes condenfations, de meme qu’en 
<c bas, & qu’en Europe. Voyage de Mejf. Bouguer, 
de la Condamine, pour determiner la figure de la Terrex 
P- 39- 
Thefe gentlemen found the mercury to rife feldom 
above twenty inches, at the city of Quito. At firft 
they felt fome uneafinefs in their breathing, and fuch 
*of their company as had weak lungs fpat a little blood} 
:but thefe complaints gradually wore off. On the Nature and 
in them and in the fecond, by means of 
the immenfe weight of atmofpheric air 
preffing upon them. The difference be- 
tween the weight which preffeth on the 
body of a man in one of the Newcajile coal- 
pits, and what would prefs upon the fame 
pian if he were on the top of one of the 
Andes, being calculated to amount to 
fomething about eight tons *. 
Many of the phyliologifls have ima- 
gined, that the animal fluids are furnifhed 
* The mechanical phyficians account for this mat- 
ter by faying, that the impetus of the heart increafes 
as the refinance to the circulating force of the blood 
increafes. 
4< The weight of the air increafing, the lungs will 
f1 be more forcibly expanded, and hereby the blood 
more intimately broken and divided, fo that it be- 
*c comes fitter for the moft fluid fecretions, fuch as 
fc that of the animal fpirits, by which the heart will 
be more ftrongly contracted. The blood’s motion 
to the furface of the body being obftruCted, it will 
fc pafs in greater quantity to the brain, where the pref- 
f‘ fure of the air is taken off by the cranium, and upon 
?4 this fcore more fpirits will befeparated, whereby the 
f4 heart will be fo ftrongly contracted as to carry on 
*4 the circulation through the paflable canals, whilft 
?4 fome other are obftruCted =” Walnewright on thenon- 
riaturals, p. 92. Properties of Fixed Air. 
with air by the lungsj but the objections* 
againfl this opinion are fuch as cannot 
eafily be iurmounted j they mull therefore 
be fupplied by the way of the chyliferous 
canals, and that in no fmall quantity for 
the air, like all other animal fluids, will 
require to be perpetually renewed : old 
particles will every moment fly off, and 
new ones mufl: of courfe fucceed. 
The air appears to be thrown off by 
urine, but chiefly by perfpiration. 
It can be demonftrated that the urine 
contains much air, but I do not know of 
any experiment to fhew that the perfpirable 
matter contains air; however, I appre- 
hend it may be aflerted with great fafety, 
that this fluid, which is the lighted; of all 
animal fluids, is the principal vehicle of the 
effete and ufelefs air *f\ 
But there are many ways of proving 
the exigence of air, in every other part of 
an animal body. 
* They may be feen at large in Haller Elementa Phy- 
/iologies, tom. iii. and in Hoffman, in the chapter deSan- 
guinis Circulo per Pulmones. 
f Experiments were afterwards thought of, and made, 
which demonftrate the prefence of air in the fweat and 
perfpirable matter. The reader will meet with them 
in the fifth Effay, 72 
On the Nature and 
Dr /Hales found, that “ a cubick inch 
“ of hogs blood, diftilled to dry fcoria, 
“ produced 33 cubick inches of air, which 
“ air did not arrive till the white fumes 
“ arofe.” fExp. 49 ) 
“ Less than a cubick inch of tallow, 
t( being all diftilled over into the receiver, 
“ produced eighteen cubick ipches of air.’* 
fExp. 50.) 
“ Half a cubick inch of the tip of a 
€( fallow deer’s horn being diftilled, pro- 
st duced 117 cubick inches of air, which 
“ did not begin to rife till the white fumes 
“ arofe.” fExp. 51.) xt Thus it ap- 
Si pears, that the cohefion of animal fub- 
t( ftances was not diftolved, even in the 
“ bloody without confiderable violence of 
te fire; though it is fometimes done to a 
(e fatal degree, in our blood, by that 
i6 more fubtile diflblvent fermentation *.” 
“ Sixteen cubick inches of fheep’s 
(C blood being put into a bolt-head, with 
e( a little water to make it ferment the bet- 
“ ter, in eighteen days generated 14 
i( bick inches of air.” fExp. 80.^ 
* As Dr. Hales held putrefa&ion to be only a degree 
of fermentation, he therefore ufeth the terms promif- 
cuoufly. Properties of Fixed Air. 
73 
So far Dr. Hales ; but I was defirous of 
knowing whether the fixed air would pafs 
from a putrefying, animal fubftance, into 
the caufiic volatile alcali, fo as to make the 
faid alcali become mild and effervefcent„ 
EXPERIMENT 16. 
Tn order to try this, I filled the two- 
ounce phial (A) fig. 3, with frefh mutton, 
cut into fmall pieces, and poured in as 
much water as ferved to fill up the in- 
terftices ; into the neck of the phial, one 
leg of the bended glafs tube (B) was in- 
ferted, and clofely luted; and the other 
fixed into a little phial (C) containing 
about a drachm of the fpirit of fal ammo- 
niac made with quick-lime. 
The phials thus joined together, were 
hung up in the common temperature of 
the air. In four days the elaftic vapour, 
in the larger phial, had fo expanded itfelf, 
that the liquor was raifed fome inches in 
that leg of the tube which belonged to it, 
but upon agitation it fubfided : And this 
agitation I was afterwards obliged to re- 
peat feveral times, otherwife the putrid li- 
quor would have run over into the fmali 
phial.  On the Nature and 
74 
When they had remained in this fitua- 
tion for a fortnight, and that I faw the 
mutton was become highly putrid, I took 
oft the fmall phial with the alcaline fpirit, 
and found, upon dropping in fpirit of vi- 
triol, that a violent effervefcence enfued. 
So that here was a demonjiration, that du- 
ring the progrefs of putrefaction, there is 
continually fome volatile matter flying off 
from the putrifying fubftance, and that 
this fugitive principle is air, which is now 
extricated, and thrown off, from a fixed 
and non-elafiic flate, into one that is vo- 
latile and elafiic-, but which, immediately 
upon meeting with a proper recipient, re- 
turns again to its former nature. 
Whether a communication with the 
external air be abfolutely neceflary to the 
extrication of the fixed air, is a matter in 
which I am not altogether fatisfied : The 
common notion concerning putrefaction, 
which is univerfally taught, and as gene- 
rally believed, is, that bodies become pu- 
trid becaufe that air hath accefs to thenit 
and communicates fomewhat; and few 
people feem to have any idea that putrefac- 
tion enfues in confequence of the lofs of 
fome principle; which, however, appears Properties of Fixed Air. 
to be the real caufe. For it will be fhewn. 
hereafter, that the methods to preferve 
bodies from putrefadlion and decay depend, 
almoft in every inftance, on reflraining the 
flight of the fixed air j for, as this princi- 
ple cements and binds together the con- 
Rituent particles of bodies, rottennefs, or 
putrefadlion, which confifls in the refolu- 
tion and difunion of thefe particles*, will 
not take place while the cementing princi- 
ple is prefent. 
But, in order to determine fomewhat, if 
poflible, concerning this affair, I made the 
following experiment. 
EXPERIMENT 17. 
In the beginning of June, the thermomet- 
er being then about 60, I took three little 
pieces of frefh mutton (of about 5i) one 
was put into a tea cup, and melted fuet 
poured all around, fo as to cover it in- 
* We muft obferve here, however, that to confli- 
tute putrefadtion there mull not only be a refolution 
and difunion of the feveral conftituent particles, but 
there muft alfo be a different difpofition, and a new 
combination of thefe particles ; barely withdrawing the 
fixed air, only deftroys the cohefion of bodies. See the 
26th experiment of this prefent Effay.  On the Nature and 
76 
tirely; the fecond was placed under a cup- 
ping glafs, which refled upon a piece of 
wet leather lying on the cover of a book ; 
and all the air that could be exhaufled was 
pumped out of the glafs, by means of the 
little air-pump belonging to it; and the 
third piece of the mutton was left expofed 
to the open air of the chamber. 
At the end of fixty hours, the piece in 
the open air, though a good deal dried, 
was found to have grown evidently putrid. 
I then went to examine the piece in vacuo, 
and could plainly perceive by its aprearance 
through the glafs, that it was become 
highly putrid, for it had grown mouldy; 
and upon lifting up the cupping glafs, 
which was now loofened from the leather 
on which it refled, the fmell fufficiently 
confirmed this appearance, for the putrid 
flench was by many degrees more ofifenfive 
and flrong than in the piece which had 
been expofed to the open air. 
Upon uncovering the bit of mutton 
which lay involved in the fqet, it was 
found perfectly fweet. Properties of Fixed Air. 
77 
EXPERIMENT iS. 
I resolved, however, to repeat this 
experiment, and that with a flill greater 
degree of accuracy and attention •> and for 
this purpofe having provided a tight air- 
pump, I took four little pieces of frefh 
beef, the firfl being weighed, its weight 
was found to be exactly 458 grains: this 
piece was placed at eight in the evening 
(thermometer being at 70) under a fmall 
receiver, and all the air that could be ex- 
haufted was pumped out; the fecond 
piece, weighing 431 grains, was covered 
with an inverted glafs of the fame capacity 
with the receiver, and relied on a piece of 
wet leather, ip read over the’ bottom of a 
China plate j the third piece of the beef, 
which was nearly of the fame bulk with 
the other two, I put into a cup, and 
poured melted fuet all around, and over it; 
and the fourth piece of the beef was hung 
up in the open air, on the north fide of the 
houfe. 
When twenty-four hours were elapfed, 
I took out the piece of beef which had lain 
in vacuo; it had fairly got the offenfive 
putrid fmell, and being weighed, was 78 
On the Nature and 
found to have loft between feven and eight 
grains. 
The piece, No. 2, which had lain un- 
der cover, was ftill perfectly fweet, and 
had loft only two grains and a half. 
The piece in the open air was almoft 
dry, and perfectly fweet. 
The piece covered over with fuet was 
not examined, as I intended it ftiould re- 
main in that fituation for fome days longer* 
Having placed No. 1 again under the 
receiver, and exhaufted the air, it was left 
there till morning; when being again ex- 
amined, it was found quite putrid, and 
wanted fifteen grains. 
No. 2 had now likewife got the putrid 
fmell, and being weighed, was found to 
have loft but five grains in all; fo that the 
piece which had lain in vacuo loft upwards 
of tV, while the other wanted only tv part 
of its original weight. 
This lofs I looked upon to be chiefly 
air, for both the pieces appeared and felt 
as foft and moift as they did at firft 5 and 
as they had lain both of them upon wet 
leather, which is but little adapted to ab- 
forb watery vapours, I did not imagine 
that much of the aqueous part could Properties of Fixed Air. 
79 
have been exhaled from either ; but the 
difference of lofs between the two muff 
have confifted entirely of air, fince the 
circumftances of both pieces were exactly 
alike, with regard to the exhalation of 
their water, both of them being inclofed 
in veffels of the very fame fize, and both 
of them alike excluded from communica- 
tion with the external air. 
The piece which had been expofed to 
the open air was found, in thirty-fix 
hours, to have grown perfectly hard and 
dry; but was quite fweet, and remained 
fo, being now rendered incapable of putre- 
faction, by reafon of the fuddden exhala- 
tion of its acqueous part; for, as hath 
been elfewhere obferved, there can be no 
fermentation, and confequently no putre- 
faction, without the requilite quantity of 
water; for water, by giving fluidity to 
bodies, allows the other principles to fhift 
their places, and to exert their feveral pe- 
culiar attractive powers, which they can- 
not poflibly do in a ffate of too much dry- 
nefs. 
And hence we fee the plain and obvious 
reafon why a moift atmofphere promotes 
putrefaction; for, independent of the pu-  On the Nature and 
trefadlive miafmata, which are fometimes 
contained in it, and which a<5t upon bodies 
as ferments, at the fame time that the 
efcape of the fixed air is favoured by the 
fmaller degree of preSTure, all the water of 
the putrefcent fubffance is left behind and 
even in fome cafes this very water is in- 
creafed, which adds to the fluidity, or 
foftnefs of the body thus expofed. 
Having Suffered the piece which was 
covered with melted fuet to remain un- 
touched for three whole days and a night, 
I opened it, and found the beef perfectly 
found, foft, and fweet; but it grew very 
putrid in eight or ten hours after it was 
uncovered, and that a way was made for 
the fixed air to efcape. 
EXPERIMENT 19. 
I repeated this experiment again with 
two pieces of frefh mutton ; the weight of 
the firft piece, which I put under the ex- 
haufted receiver, was 573 grains; the 
other, which was covered by the inverted 
glafs, weighed 554 grains. 
After remaining twenty-four hours, 
I found them both tainted, the weather 
being at this time very moift, as well as Properties of Fixed Air. 
tvarm; but upon weighing, the proportion 
held nearly as before ; for No. i loti more 
than five grains, while No. 2 wanted only 
tv/o. 
EXPERIMENT 20. 
I then took two freih eggs, which had 
been laid the fame day, and put one of 
them under the receiver, where it was 
kept for a week, and the air-pump wrought 
generally once in the day, in order to keep 
it as much exhaufted as pofiible; the 
other egg was left in the open air. At thef 
end of the week, I broke them both, and 
found the one which had been under the 
receiver, though it could not be faid to be 
rotten, yet had acquired fome degree of 
fcetory and the yolk did not appear near 
fo firm as the one which had been expofed 
to the open air. 
The broken eggs happening not to be 
thrown out, I found the one which had 
been kept in the receiver of the air-pump 
quite putrid and ofrenfive, on the follow- 
ing morning, while the other remained 
perfectly fweet. 
It is univerfally known, that eggs, 
when coated over with melted fuet, or 82 
On the Nature and 
fome fuch unCtuous matter, will remain 
frefh and found for many months. 
EXPERIMENT 21. 
With the apparatus belonging to an 
air-pump, there are generally two hemi- 
fpheres of metal, contrived to join clofely 
together, fo as that when the air is pumped 
out of the cavity, the two remain firmly 
united by the mere prefiure of the atmof- 
phere. 
It did not at firft occur to me, that it 
would be befl to inclofe the pieces of meat 
that I wanted to make the experiments 
on, in this hollow globe, which promifed 
to exclude the external air more effectually 
than was done in the former way. 
Having therefore inclofed a piece of 
fweet and frefh mutton in this fphere, and 
left another, of the fame bulk, under co- 
ver of a glafs, they were both fuffered to 
remain in thofe fituations for forty-eight 
hours. 
Upon examination, the piece which 
had been inclofed in the hollow fphere 
was found fweet, and the other putrid. 
This being a more complete vacuum 
than any I had been able to make in the Properties of Fixed Air. 
glafs receivers (for they generally loofened 
in twelve or fourteen hours; I found that 
the afiertion, “ that bodies do not readily 
“ become putrid, when perfectly fecluded 
“ from the external air,” may neverthelefs 
be true, notwithstanding what has been 
feen in the four preceding experiments * $ 
which, however, prove inconteftably, that 
removing the preffure of the atmofphere to 
a certain degree, does facilitate the efcape 
of the fixed air from bodies; though per-* 
haps a total cutting off all communication 
between the putrefeent body and the ex- 
ternal air, may render the flight of this 
cementing principle more difficult -f*. 
* I am fenfible that the experiments above-reel ted 
were not made with fufficient accuracy to determine; 
the point in queftion. The putrefeent fubftances ought 
to have been inclofed in receivers, cemented to a plate 
of metal, or glafs ; and thefe receivers ought alfo to 
have included a mercurial gage. This was the method 
pra&ifed by Mr. Beyle; who relates, that he found 
oranges, lemons, and four grapes, with their feveral 
juices, free from putrefaction or mouldinefs, at the end 
of three years ; but a liquor, fuppofed to be frog’s 
fpawn, was found black and fetid at the three years 
end. 
•f It was the opinion of Boerhaave, that there is a 
confent between the atmofpheric air and the air inclofed 84 
On the Nature and 
Dr. Pringle having found the f eft ace a, 
and abforbent earths, to be promoters of pu- 
trefaction, this feemed the proper time for 
repeating thofc experiments. 
EXPERIMENT 22. 
Accordingly, I began with chalk, 
and the pulv. e chelis cancrorum comp, of 
the fhops; two phials, each with half a 
drachm of thefe powders, mixed with an 
ounce of water, had feverally a fmall bit 
of frefh beef put into them ; a third phial, 
with nothing but water and a bit of the 
fame frefh beef, ferved as a ftandard. 
In thirty-fix hours, the two phials with 
the abforbent powders had both got the 
putrid fmell; in three hours afterwards, 
the piece of beef in the third phial became 
likewife fetid. 
in the fubftance of bodies ; and that, as the external- 
air is in a perpetual courfe of variation, fo likewife is 
this internal air ; therefore, when all communication is 
cut off, the motions of the one are not followed by 
the other. “ Hinc forte fit quod omnes praecipuae ac- 
ts tiones naturales abfolvuntur in aere communi non 
M in vacuo Boyleano.” Elem. Chem. tom. i. p. 539. Properties of Fixed Air. 
85 
EXPERIMENT 23. 
A like quantity of the chalk andpuhis 
e chelis was put into two phials, with an 
ounce of water in each, and half an ounce 
of frefli ox-gall. A third phial, with no- 
thing but gall and water, ferved as a flan- 
dard. 
In thirty-fix hours, the two firil phials 
were found putrid 5 the third maintained 
its fweetnefs for about fix hours longer. 
EXPERIMENT 24. 
Half a drachm of the earth of allum, 
mixed with an ounce of water, and a little 
bit of frefli mutton, were put into one 
phial; half a drachm of magnefia alba, 
mixed with an ounce of water, and a bit 
of the fame mutton, were put into afecond 
phial ; a third bit of the mutton was left 
in a cup, with common water, for a flan- 
dard. 
It was about three in the afternoon 
that thefe mixtures happened to be made; 
they were all fweet at bed-time on the fuc- 
ceeding night, after having flood thirty 
hours; but next morning, the mutton, in 
both the magnefia and the flandard, was 86 
On the Nature and 
found putrid, but the magnefia rather more 
fo than the fimple water. 
The earth of allum preferved its piece 
of the mutton twelve hours longer, and 
rendered it fomewhat hard; pofiibly, fome 
fmall remains of the acid adhered to the 
earth, which gave it this flight degree of 
antifeptic power. 
Dr. Pringle s conjecture about the man-' 
ner of operating of thele abforbents, is, 
that they deftroy the latent acid. 
This latent acid is fuppofed to enter into 
the compofition of animal bodies, and is 
conceived to be one of the chief ingre- 
dients in the cement between the particles 
that conflitute the fibres ; chalk and tejlacea, 
therefore, aCt as difiolvents, by being the 
proper abforbents thereof. 
This latent principle, however, is al- 
lowed to be fo much out of the reach of 
demonflration, that the doCtor fays, “ It 
“ may be hard, or even impoflible, to pro- 
g‘ duce it'in a fimple form.” 
But there is another principle in ani- 
mal bodies, of whofe exigence there can 
be no doubt, the fixed air ; and this makes 
the chief ingredient in the cement which 
binds together the particles that conflitute 
the fibres. Properties of Fixed Air. 
Calcareous earths have a very ftrong 
affinity with this fixed air ; and though, 
in a natural flate, they abound greatly in 
this principle, yet from their action of 
haftening putrefaction, it appears very 
plain, that they are not fo replete with 
fixed air, but that they are ftill capable of 
extracting fome from an animal fubftance, 
and thereby promoting the inteftine mo- 
tion. For the extraction offome portion of 
the fixed air feems fufficient to throw the 
remainder of that element into aCtion, and 
thereby to raife the inteftine motion; be- 
caufe, when the fixed air flies off fpontane- 
oufly from any fubftance, it always re- 
fumes its elafticity, or repulfive power, in 
the infant of its extrication ; and this re- 
pulfive power it is that puts the other prin- 
ciples into motion. 
But when the whole of the fixed air is, 
withdrawn from a body, by any fubftance 
having a ftronger affinity therewith, fuch 
as quick-lime, then the fixed air, fo at- 
tracted or abforbed, does not regain its 
elafticity, but pafleth, in a no?i-elaftic ftate, 
from one body to another; and hence en- 
fues the dijfolution, but not putrefaction, 
of the body whofe fixed air is fo carried off. On the Nature and 
EXPERIMENT 25.' 
I put half a drachm of quick-lime into 
an ounce of water, and immerfed therein 
a little bit of freih mutton. This mixture 
kept off the putrefaction, but it intirely 
diffolved the Befh, in about a week; not 
the lead: ill fmell, however, was to be per- 
ceived, although I kept the mixture for 
three weeks in all. 
Seeing then, that dead bodies become 
putrid from the lofs of their fixed air*, 
* I h^vejuft met with a book pYiblifhed at Vienna in 
J762, wherein the author endeavours to eftabifh a very 
extravagant theory concerning putrefaction and con- 
tagious difeafes. 
He infifts, that bodies which are vulgarly fuppofed 
tq putrefy, or to rot, are devoured by myriads of ani- 
malcula \ that the factor arifing from fuch bodies arifeth 
from the excrements of the faid animalcula; and that 
contagion is fpread by their ova being wafted through 
the air, and carried from place to place. 
Hence he attempts to account for the appearances in 
the fmall-pox, meafies, fcarlet-fever, and all othey 
contagious or infectious difeafes ; alledging the caufe 
of all thefe to be a materia animata, or feminium ver- 
minnjum. 
I he confequence of this theory is, that mercury, and 
the bitter anthe'tminthics, are the only things whereby 
v/e are to expedt to do fervice in thefe difeafes. Marci 
Anton. Plenciz Opera Medico- Pbyjica. Properties of Fixed Air. 
may not the immediate caufe of putrefac- 
tion in living bodies be the detachment of 
too large a proportion of their fixed air ? 
In order to fee what foundation there 
may be for this conjecture, let us take a 
view of the appearances which attend the 
putrefaction of animal fluids. 
Dr. Pringle remarked, “ That both 
the ferum and craflamentum of human 
“ blood yielded air, after Handing fome 
“ time in the lamp furnace, before any 
<f offensive degree of putrefaction was par- 
“ ceived.” 
“ I have known (fays Dr. Huxham *J 
(f the whole body fwell vastly, even to the 
“ ends of the fingers and toes, with a ca- 
“ daverous lividity, though almoft quite 
“ cold, and an intolerable ftench, even 
“ before the perfon was actually dead; 
blood ifluing at the fame time from the 
“ ears, nofe, mouth, and guts: And this 
<f too where the pulfe had been very weak 
“ and fmall, though exceeding quick from 
*f the very beginning. Was not this from 
** much air generated by the inteftine mo- 
‘f tion, heat, and putredity, which are 
* In his Treat ife on the Malignant Sore-Throat, p. 6j. 90 
On the Nature and 
well known to generate air ? Is not the 
t( emphyfe7na obfervable in fome fphacela- 
*( tions, from the fame caufe ?” 
Many fymptoms of this fort, in the 
fcurvy, and other highly putrid difeafes, 
evidently fhew that the air is actually de- 
tached from the blood in thefe terrible 
cafes. 
Let us now obferve the known caufes 
of that degree of putrefaction, which often 
takes place in the living body. 
First, a long continuance in an over- 
moijl air is known mod certainly to bring 
on the putrefactive diathefis. 
An atmofphere full of watery vapours 
obdruCts perfpiration, not only by leffening 
the force of the relaxed folid fibres, and 
thereby hindering them to propel the ufual 
and natural proportion of perfpirable mat- 
ter to the furface of the body, but fo much 
of this matter as is driven on, when it ar- 
rives at the proper out-lets, finds an at?nof- 
phere already loaded with water, and confe- 
quently ill adapted, and little capable of 
abforbing much of the fame kind of va- 
pour ; an animal body, therefore, in this 
date of the weather, may be faid to be Properties of Fixed Air. 
nearly in the condition of a wet cloth hung 
out on a damp day. 
But the perfpirable matter conflds of 
other principles befide water; its tade 
proves it to contain a large {hare of fait $ 
and the reafon of the thing may warrant 
us in aflerting, that it has fome portion of 
earthy and phlogiftic, or oily matter, in its 
compofltion; and, in particular, that it 
carries off a great deal of air *. 
The lighted: and mod fugitive part of 
this excrementitious fluid, that is, its aerial 
part, may be carried off, notwithdanding 
the moid date of the atmofphere will not 
allow the aqueous part to be exhaled : A 
great {hare of the water, therefore, and 
the three other principles joined to it, be- 
ing left behind, now they are deprived of 
their air, are in a putrefatfive fate, and 
confequently may be become ferments to 
the remaining mafs of fluids. 
* Cum totum corpus noftrum innumeris tubulis & 
poris pervium atque vafculofum fit, per quod, continuo 
& perenni motu, aeftuantes humores circumferentur, 
non mirum eft, ingentem copiam tenuiflimorum cor- 
pufculorum aqueo-aereorum, & fulphiireo-falinorum, modo 
fub forma vaporum, modo humoris, per illud evehi. 
Hoffman. Med. Syji. Rational. pars iii. cap.vii. feet. u. 92 
On the Nature and 
If we attend to the known methods of 
preferving health, while the body is ex- 
pofed to too great a degree of moifture, 
the above hypothecs will appear the more 
rational; fince experience teacheth, that 
this is moft effectually done, i, by keep- 
ing the body well covered, and wearing 
fuch kind of apparel as will mofl readily 
abforb the watery part of the perfpirable 
matter which the atmofphere cannot ab- 
forb ; 2, by ufing fuch a courfe of diet as 
will afford the animal fluids more than 
ufual fupplies of air, to make up for the 
-extraordinary wafte, fuch as recent vege- 
tables, fruits, fugar, and aromatics; 3, 
by eating fparingly of animal food, which 
yields a fmall proportion of air, and by ab- 
itaining from the immoderate ufe * of ar- 
dent fpirits and fermented liquors, which 
gheck the alimentary fermentation, and 
hinder the free extrication of air from the 
fubflances fed upon. 
Secondly, if the circulatory motion of 
the fluids be very much increafed, either 
* The moderate ufe of thefe liquors may be found 
of fervice as ftrengtheners, to encreafe the power of 
the folids, and thus enable them to keep up a due de- 
gree of perfpiration. Properties of Fixed Air. 
by too violent exercife, or by a fever, and 
this extraordinary motion be continued, 
putrefaction mod certainly enfues. 
It is evident, that the immediate effeCt 
of this extraordinary motion and violent 
agitation of the blood, muft be a difunion 
of its component parts here then, the 
aerial part will be the readied; to fly off, 
and will be carried in great quantities to 
the furface of the body; there it muft 
efcape, and when it does efcape, we know 
what muft be the confequence*. 
Thirdly, mercury, and many of the 
poilons, deftroy the texture of the fluids. 
The aCtionof mercury may be confldered 
either as breaking down the particles of 
the blood by its extraordinary weight, and 
the force of mere mechanical attrition, or 
it may be fuppofed to aCt in confequence 
of its having a power to change the natu- 
ral laws, which obtain among the repul- 
iive and attractive powers of the feveral 
* Hence the propriety of the practice, fo much in- 
filled on and recommended by Sydenham, in the firft 
five or fix days of the fmall-pox, and in the commence- 
ment of putrid fevers; namely, not to overheat the 
patients, either by diet or medicine, or by fuffering 
them to lie continually in bed,  On the Nature and 
condituent particles: And this lad; feems to 
be the mod plaudble way of accounting 
for its operation; fince the quantity of 
mercury, when rendered active by its being 
joined to fome faline body* which is found 
fufficient to melt down the blood, is fo ex- 
tremely fmall in many cafes, that no me- 
chanical adtion, arifing from its weight, 
can be deemed equal to the effeCt. The 
aCtion of poifons, to which are to be re- 
ferred infectious jniafmata caudng putrid 
difeafes, cannot well be accounted for, nor 
any other principle, than by recurring to a 
power of this lad-mentioned kind ; feeing 
their quantity is fo exceeding fmall, that, 
let them be fuppofed to confid of the 
fharped of all podible darts or fpicula, they 
* The reafon that mercury becomes fo extremely 
a&ive, when joined to faline bodies, I take to be this: 
It is now rendered capable of the molt immediate and 
intimate mixture with the animal fluids, becaufe of the 
affinity between water and fait; and being thus mixed 
with the mafs of blood, can change the repulfive and 
attra&ive powers in fuch a manner as to produce a new 
combination among the conftituent particles. 
It is impoffible to demonftrate this aflertion by ex- 
periment j but a variety of circumftances in chemiftry 
may ferve to give an idea of the manner in which it 
may be brought to pafs. Properties of Fixed Air. 
never could occafion fuch alterations, or 
dedroy the texture of the fluids in fuch a 
manner, as experience fhews may be done, 
in a very fhort fpace of time, by the intro- 
duction of thefe fubtile and aCtive matters 
into the blood. 
Fourthly, a diet confiding entirely of 
animal food, excepting in very cold cli- 
mates *, is followed by a putrefactive dif- 
folution of the fluids. 
The flefh of animals undoubtedly con- 
tains oil and fait, of a more fharp and ex- 
alted nature than are to be found in the 
fubftance of the efculent vegetables ; there- 
fore, a diet confiding wholly of defh can- 
not fail of producing chyle replete with 
thefe acrid principles ; but animal food ap- 
pears likewife to yield but little air, as may 
be inferred from remarking the druCture 
* The natives of Greenland, together with the EJki- 
ntaux Indians about Hudson's Bay, and many of the Tar- 
tar nations, feed wholly upon flefh or fifh, and fome 
of them do not fo much as drefs it. 
But in thefe very cold climates, the wafte of air by 
perfpiration muft be confiderably lefs than it is within 
the tropics, where it would be impoffible to live in this 
manner for many days without bringing on fome pu- 
trid difeafe. 96 
Oii the Nature arid 
of the alimentary canal in carnivorous ani- 
mals, vvhich is much Shorter, has fewer 
ruga, and does not at all feem adapted to 
the different degrees of diftention, which 
the ilomach and inteftines of the creatures 
who feed altogether on vegetables, or on a- 
mixed diet, are capable of. 
It will appear hereafter from experi- 
ments, that air actually has the power of 
correcting putrid acrimony, when formed p 
and therefore, it can be no unfair infer- 
ence to prefume, that it has the power to 
'prevent this acrimony from taking place r 
Hence every fort of food, that affords not 
the due proportion of this element, is al- 
ways found to promote putrefadron ; as 
many inffances in the hiftory of difeafes 
abundantly prove; where feme of the mod: 
deftrudive putrid difeafes appear evidently 
to have been occafioned by feeding on da- 
maged vegetables, which are incapable of 
fermentation, and confequently incapabl© 
of producing the requifite quantity of air; 
for this it apparently is that invigorates the 
chyle, and enables it to fupply good and 
wholefome blood. 
But if wanting the due proportion of 
air be fufficient to induce the putrefadive Properties of Fixed Air. 
diathejis, what muft a total want of this fa- 
lutary principle produce ? Accordingly, in 
thofe melancholy inftances where people 
have perifhed through hunger, the hu- 
mours have been found highly putrid; for 
the addon of the body difpels all the lighter 
aqueous and aerial part, while the oily and 
the [aline are left behind. 
The mechanical phyficians think they 
give a juft idea of putrefadive acrimony 
when they tell us, that it confifts in the 
letting loofe of certain fharp pointed parti- 
cles, which either exift naturally in the 
fluids (but, in a healthy ftate, are pre- 
vented from doing any harm, by fheaths or 
involucra which cover them); or, that 
thefe pointed particles arife from the break- 
ing of the globules, which thus become 
flaarp and angular, like the others before- 
mentioned and, like them, are now ca- 
pable of tearing, irritating, and deftroying 
every thing they meet with*. 
The foundnefs and the corruption of ani- 
mal fluids feem to depend more upon che~ 
mical mixture, than on ?nechanical adlion rj-; 
* Vide De Gorter de Perfpnatione, in cap. vii. p. 42. 
f That is to fay, animal fluids do jiot contain fharp 98 
®n the Nature and 
and yet thofe chemifts who made putrefac- 
tion and alcali much the fame thing, and, 
in confequence thereof, were to cure all 
putrid difeafes by acids, have not, by this 
theory, added much to the true improve- 
ment of medical knowledge. 
But a very eminent practitioner,' and 
admired writer, who has thrown great 
light on this part of medicine, finding that 
fyrup of violets was not changed to a green 
colour by the ferum of putrid blood ; that 
this ferum did not make any effervefcence 
when fpirit of vitriol was poured on it; that 
water, in which corrupted defli had been 
fometime infufed, neither effervefced nor 
changed the colour of the fyrup ; and that 
alcaline falts, both fixed and volatile, pow- 
erfully oppofe putrefaction ; can by no 
means bring himfelf to believe that putrid 
pointed or angular particles, that are capable of being 
pbtunded, or brought into the globular form, by merely 
rubbing againft each other in the courfe of circulation. 
But thefe fluids confift of particles which all have their 
feveral peculiar affinities, or attra&ing and repelling 
powers, with regard to each other, whereby they are 
capable of forming a great variety of combinations, in 
a manner fimilar to what is obfervable in chemical 
jruxtures. Properties of Fixed Air. 
animal fubdances fhould be regarded as al- 
caline. 
Having made feveral experiments in 
order to fatisfy myfelf in this matter, I 
diall here lay an account of them before 
the reader. 
EXPERIMENT 26. 
Human blood being left in a phial well 
corked, at the end of two months was 
found highly putrid; it had not feparated 
into diftindt parts of ferum and crajfamen- 
turn, but was all alike thick, being of the 
confidence of lyrup, and of a dark red, or 
rather blackifh colour. 
Spirit of vitriol being dropt into fome 
of this putrid blood, raifed a lhnart effcr- 
vefcence, and converted it into a hardened 
fpongy kind of fubdance. 
EXPERIMENT 27. 
Six ounces of this putrid blood being 
put into a fmall retort, with two fpoon- 
fuls of water, were diddled by a very gen-* 
tie heat; about an ounce and half of a 
tranfparent liquor having come over, the 
receiver was taken off, and the liquor found 
to be a phlegm, with a very pungent, and  On the Nature and 
peculiar fetid flavour, not like that of the 
blood from which it was obtained, hut ra- 
ther more approaching to the fmell of rot- 
ten fifh. 
This fpirit effervefeed violently, with 
the acid of vitriol. 
It changed the juice of rhadifh ferap- 
ings to a bright green *. 
It threw down a white precipitate, from 
a folution of corrofive fublimate. 
It turned a folution of copper in an acid 
to a bright blue. 
And when faturated with the acid, and 
its pungency thereby deflroyed, when feme 
fixed alcali was dropt in, the volatile pu- 
trid alcaji immediately began to fly off, 
and ftruck the nofe with the peculiar fmell, 
as ftrong as at firft. 
So that here are all the plain and diflin- 
guifhing characters of the volatile alcali. 
* The fcrapings of radilhes afford 3 blue juice, 
which anfwers much better to try acids and alcalies 
than fyrup of violets : The moft convenient way is to 
dip little bits of linnen-rag in the juice, and having 
dried them, lay them by for ufe. Properties of Fixed Air. 
EXPERIMENT 28. 
With regard to the putrid bile, the 
f<ztor here is not at all like, nor indeed fo. 
pungent or offendve, as the flench qf pu - 
trid flefh, or putrid blood ,* having an oily 
fmell, notunlike flinking olive oil. 
Putrid bile (it was ox-gall that was 
tried) Ihews no iign of alcali; it neither 
effervefceth with acids, nor does it change 
the colour of the blue juices ; neither does 
it throw down any precipitate from thefo- 
lution of the corrofive fliblimate. 
EXPERIMENT 29. 
Two ounces of this putrid bile, being 
diftilled by a gentle heat, and two or three 
drachms of a tranfparent liquor having 
come over, the receiver was taken oft, and 
the produce found to be a volatile fpirit, 
with a peculiar fetid fmell, and a confider- 
able degree of pungency ; this fmell differs 
from that of the putrid bile itfelf, but ap- 
proacheth nearly to that of the fpirit ob- 
tained from the putrid blood, though not 
fo pungent. 
But this fpirit made no effervefcence 
with acids; and when mixed with the fo~  On the Nature and 
lution of the fublimate, it threw down btf£ 
little precipitate, even lefs than frefh urine 
did, when mixed with the fame folution ; 
neither did it turn the blue juice to a green 
colour ; fo that here there were fcarce any 
figrts of an alcali: The only circumftance 
wherein it manifefted the alcaline nature, 
tvas when faturated with fpirit of vitriol; 
for when its pungency and feetor were de- 
ployed, by the power of the acid, upon 
adding the fixed alcali, the peculiar fmell 
of the biliofe fpirit immediately returned. 
It being fummer when I was engaged 
in the above-mentioned experiments, I 
could not conveniently get any human bile, 
but when winter came on, and the diffec- 
tions began at the anatomical theatre,- I 
feized the opportunity of collecting a quan- 
tity of that fluid; and having fuflered it to 
remain in a corked phial for two months, I 
then made the following trials. 
EXPERIMENT 30. 
I. I poured ftrong fpirit of vitriol on 
fome of the putrid bile, but found it raife' 
no ebullition. 
Having put an ounce of the putrid bile 
into a little retort, ;and placed it in a lamp Properties of Fisted Air. 
furnace* I drew off about two drachms of 
a tranfparent liquor, with a confiderable 
degree of pungency, and a fetid difagreea- 
ble fmell, like the fpirit obtained from the 
ox-gall. 
Some of this fpirit being dropt into 
fyrup of Violets, immediately changed the 
bluifh colour of the fyrup into a pale green; 
3 . When dropt into a folution of corro- 
live fublimate, it inftantly threw down a 
white precipitate. 
4. And when dropt into a dilute folu- 
tion of blue vitriol, it caufed the folution 
to grow turbid, and heightened the blue 
colour. 
5. And yet, notwithffanaing all thefe 
ftrong tokens of the ale aline nature, the ef* 
fervefcence was but very obfeure when 
llrong fpirit of vitriol was poured on the bi- 
liofe fpirit, 
EXPERIMENT 31. 
The putrid liquor which lay about rot- 
ten fleih changed the colour of the blue 
juices to a dark green. It occafioned a 
fmall precipitation when added to the folu- 
tion of corrohve fublintate, but it did not 
effervefce with the acid, until air was tranf- 104 
On the Nature and 
ferred into it, from a mixture of acid and 
alcali: This method of treatment, not 
only made it effervefee, but alfo deflroyed 
much of the putrid factor. 
EXPERIMENT 32. 
When the Fetor of this putrid liquor 
was deflroyed, by pouring vinegar upon it, 
it returned immediately, on the addition of 
fpirit of fial ammoniac. 
EXPERIMENT 33. 
The fame thing happened when the 
factor was deftroyed by the pouring of 
weak lpirit of vitriol on the fame putrid 
liquor, and afterwards dropping in lixivium 
iartari *. 
And thus we find, that as the fixed al- 
cali is ftrong enough to dilpoffefs the vola- 
tile, fo both of them have power to expel 
the fimple putrid alcali. 
For, upon the whole, we may fafely 
join with Neuman, in faying, that as foon 
as an animal fubftance begins to putrefy, 
* The acid fpirit muft here be pretty much diluted, 
©therwife it will raife a more difagreeable fator, inftead 
©f conquering the original putrid {tench* Properties of Fixed Air. 
it begins to difcover an alcaline quality, 
and this volatile matter, now produced in 
it, may be feparated by diftillation in a very 
gentle warmth. 
When I made the experiments on the 
putrid blood, related in No. 26 and 27, I 
had not obferved Dr. Lewis s note upon the 
above-recited pafiage in Neuman: and 
therefore was greatly furprized to find that 
very ingenious gentleman declare, <e That 
“ this general dodlrine of the chemifts did 
“ not appear to be ftri&lyjuftj and that 
“ they feemed to have been mis-led by ap- 
“ plying to all animal fubftances what they 
“ had found to obtain in one, but what a 
“ farther examination fhews to obtain in 
(( very few, if any befides, at lead; in any 
“ confiderable degree.” 
“ Putrid urine (fays he) gives plain 
“ marks that it contains a volatile alcali, 
“ already generated but putrid blood and 
f< flejh are not fenjibly alcaline, and yield no 
“ alcali on diftillation, till after the phlegm 
“ has arifen*.” 
After reading this note, from fo ex- 
perienced a chemift, I began to call in 
* Neuman's Chemjjiry, in the note, p. 485. 106 
On the Nature and 
queflion the evidence of my own fenfes 
and had almoil; concluded that, fome way 
or other, (though in what I could not pof- 
fibly guefs) the procefs had been mifma- 
naged. 
I therefore determined to repeat it, 
and that with the utmofl caution and ex- 
adtnefs. 
EXPERIMENT 34, 
Two quarts of human blood were put 
into a retort, which being flopped, was buf- 
fered to remain five or fix weeks, at the 
end of which time the blood was found 
highly putrid ; a receiver was now luted 
on, and the fire raifed. 
The very firft drachm or two of the li- 
quor that came over was immediately 
poured out, in order to examine it. 
It had precifely the fame fmell of the 
fpirit obtained in the former procefs ; it ef* 
fervefced with the acids, and fhewed all 
the other alcaline properties already men- 
tioned*. 
* The volatile alcali obtained from putrid fubftances 
is not exa&ly fimilar to that obtained by violent heat 
from animal fubftances not putrid* Properties of Fixed Air. 
107 
Some gentlemen of knowledge in che- 
miftry were prefent during the diftillation, 
and were all thoroughly fatisfied, that in 
this matter Dr. Lewis himfelf hath been 
mis-ledj and, very poflibly, in the fame 
way that Dr. Pringle appears to have been j 
for lince alcalies rejifi putrefaction, it was 
reafonable to conclude, that putrid animal 
fubftances were little, if at all, alcaline. 
But the principle on which this aCtion 
of alcaline falts depends, has nothing to do, 
in particular, with alcali, being, as will 
be fhewn immediately, common to all faline 
bodies whatfoever. 
It differs remarkably in the flavour, which is nau- 
feous and difagreeable, is not fo pungent, and is much 
weaker, than the common volatile alcali; fince this 
laft, as we have juft now feen, is capable of difpoffef- 
fing the putrid alcali, and of driving it off from any 
body to which it hath been united. E 8 S A Y III. 
O N T H E 
♦ 
RESPECTIVE POWERS, 
AND 
MANNER of ACTING, 
v 
Of the different Kinds of 
« 
ANTISEPTICS. Although the arguing from experiments and 
obfervations by induction, be no demonftra- 
tion of general conclufions, yet it is the beft 
way of arguing which the nature of things 
admits of; and may be looked upon as Jo 
much the fronger, by how much the in- 
duction is more general. Newton. ESSAY III. 
ON THE 
Respective Powers, and Manner 
of Acting, of the different Kinds 
of Antiseptics. 
IT was never imagined, until Dr. Pringle 
fhewed it, that the Antifeptic Power is 
fb extenlive; but it appears from the ex- 
periments made by that very judicious and 
learned phyfician, that falts of every kind, 
whether acid, ale aline, or neutral, fixed or 
volatile, as well as the aftringent and gummy- 
ref nous part of vegetables, all of them re- 
fill, and mofl of them correct putrefaction; 
and he purfued this branch of enquiry fo 
far as to enable him to form a table, fhew- 
fhing the comparative antifeptic forces of 
thefe feveral fubflances. 
His being fo very particular on this 
head rendered it unneceffary to repeat the 
experiments, with regard to all thefe dif- 112 
On the Respective 
ferent fubftances; but as I had got into the 
habit of experimenting, and found great 
fatisfaction from this method of acquiring 
knowledge, I refolved to try fome of them; 
and accordingly began with the acids, 
which, from ancient prefcription, claim 
the right of being placed at the head of 
this clafs. 
EXPERIMENT i. 
Having diluted the acids of vitriol, of 
feafialt, and of tartar, together with vi- 
negar, and the juice of lemons, all, as nearly 
as I could judge, to the fame degree of 
weaknefs, leaving them juft fo ftrong as to 
be fairly fenfible to the tafte, as to change 
the blue juices into red, and to elfervefce 
plainly, upon the addition of an alcali; I 
then put fome ounces of each into five 
phials, and in every one of them immerfed 
a little bit of frefh mutton; and a fixth 
phial, with nothing but water and a bit of 
mutton, ferved as a ltandard. 
They were all placed in a moderate 
degree of heat (on the top of the furnace, 
along with the fermenting mixtures of the 
fecond table) and fqffered to remain for 
four days. Powers of Antiseptics. 
ACIDS. 
24 Hours. 
AFTER S 
48 Hours. 
r A N D I N G 
3 Days. 
4 Days. 
(i) of Vitriol. 
Sweet. 
Sweet. 
Sweet. 
Sweet. 
(2) of Sea-falt, 
Sweet. 
Sweet. 
Sweet. 
Sweet. 
(3) of Tartar. 
Sweet. 
Sweet. 
Beginning to 
putrify. 
Putrid thrown 
out. 
(4) of Vinegar. 
Sweet. 
Sweet, and 
much fwelled. 
Sweet. 
Sweet. 
(5) of Lemons. 
Sweet. 
Sweet, and 
much fwelled. 
Sweet. 
Sweet. 
(6) Water, 
as a Standard. 
Smell grown 
offen five. 
Very fetid. 
Putrid, and 
foft. 
r 
Table III. Acids diluted tried as Antiseptics. 114 
On the Respective 
It appears by the foregoing table (the 
3d), that they were all, excepting the one 
in the acid of tartar, and the flandard, 
fweet at the end of four days. I hung up 
all the fweet pieces in the open air, where 
they foon became dry, and remained fweet. 
Thus it appears that acids, even when 
greatly lowered, have a ilrong degree of 
power to refill putrefaction. 
EXPERIMENT 2. 
Along with this parcel of acids, I tried 
the fixed and volatile alcalies, diluted to the 
fame low degree ; but though the volatile 
alcali preferved the piece of mutton im- 
merfed in it, as well as any of the acids, 
yet the lixivium tartari did not keep its 
fweetnefs much longer than the fimple wa- 
ter which ferved as a flandard. 
IrfiREsolved, therefore, to try the alca- 
lies, without lowering them fo much ; and, 
at the fame time, was defirous of feeing 
what fliare of antifieptic power was polfeffed 
by a neutral mixture. 
EXPERIMENT 3, 
Five bits of frelh mutton were put into 
as many phials, with, i, lixivium tartaric Powers of Antiseptics. 
2 y fpirit cornu cervi per fe\ 3, fpirit falls 
ammoniaci cum calce viva ; 4, fpirit us min- 
dereri; and, 5, water, as a ftandard. 
The four firft were all diluted with wa- 
ter, in the proportion of four to one; and 
all were left in the common temperature of 
the air. 
The phials were examined every day* 
for eight days ; and all of them, the ftan- 
dard excepted* which grew putrid in three 
days, found fweet; the pieces of mutton 
in the alcaliesj grew foft and white, like 
frefh fifh, but the ode in the fpiritus min- 
dereri always preferved the natural rednefs 
of the flefh. 
I now left off examining them every 
day, and having laid the phials afide for 
three weeks, found all the bits of mutton 
as fweet as they were on the firfl day. 
The power of the faline bodies was'alfd 
tried, in another manner. 
EXPERIMENT 4. 
I put four pieces of freRi mutton into 
as many cups, and poured on them feve- 
rally, i, weak fpirit of vitriol; 2, ffir it of 
hartforn; 3, lixivium tartaric and, 4, a 
neutral mixture, offixed, alcali and vitriolic 116 
On the Respective 
acid; and having fuffered them all to re- 
main about ten minutes, by which time 
they appeared to be thoroughly foaked and 
penetrated, I then threw them all into 
glades with water, and fet them by, in 
the common temperature of the air. The 
annexed table, No. 4, fhews how long 
each of them preferved their fweetnefs. 
Thus the power of falts in general', to 
keep off putrefaction, was moft fatisfac- 
torily proved ; and as this power belongs 
to faline bodies in general, it certainly muff 
depend on fome property which is commofi 
to them all as falts, fince we plainly fee 
that acid and alcali have nothing to do here. 
With regard to ajlringents, Dr. Prin- 
gle's experiments {hew them to be poffeffed 
of a very great degree of antifeptic virtue; 
for allum, galls, green tea, and red rofes, 
were all found to refill: putrefaction, with 
a power greatly fuperior to fea-falt. 
And the gum-rejins, fuch as myrrh, afa 
faetida, aloes, and terra japonica, together 
with decoctions of fuch vegetable fub- 
fiances as abound in gummy-refinous parts, 
Virginian fnakeroot, pepper, ginger, faffron, 
coutrayerva root, /age, valerian root, and 
rhubarb, with mint, angelica, fenna, and Powers of Antiseptics. 
117 
Table IV. Saline Bodies as Oppofers of Putrefa&ion. 
Spirit of 
Vitriol. 
Spirit of 
Hartfhom. 
Lixivium 
Tartari. 
Neutral 
Mixture. 
Water, 
as a ftandard. 
Remained 
fweet 28 Days. 
Remained 
fweet 8 Days. 
Remained 
fweet 4 Days. 
Remained 
fweet 14 Days. 
Was putrid in 
36 Hours. 118 
On the Respective 
common wormwood, all of them (hewed great 
antifeptic power *, but none of them came 
up to camphire, in this refpeCt, which Dr. 
Pringle thinks may be allowed to keep off 
putrefaction, with a power three hundred 
times greater than fea-falt. 
Many of the common efculent vegeta- 
bles, horfe rhadijh, mujlard, carrots, tur- 
tle} s, garlic, onions, cele?y, cabbage, and 
colewort, were likewife found to keeD back 
putrefaction. 
But I do not know how it happened to 
Dr. Pringle *, that he fhould find lime wa- 
ter, only, to make fome fmall refiffance 
to putrefaction,” lince lime-water has been 
univerfally known, to be very powerful in 
this refpeCt; and the late Dr. Alfton, who 
Was a man of very great candour and veracity, 
* See his 27th experiment. 
Dr. Pringle, however, may be juftified in not allow- 
ing lime--water to be an antifeptic; for, in order to 
ponftitute a true antifeptic, it is not only requifite that 
pnere be a power to prevent the inteftine motion, but 
alfo to preferve the firmnefs and cohefion. Now lime- 
water, though it prevents the inteftine motion, and 
confequently hinders the generation of the putrid al- 
cali, yet, by abforbing the fixed air, it deftroys the co- 
fiefiop of the conftituent particles. Powers of Antiseptics. 
119 
relates a number of experiments, in his 
Differtation on Quick-lime, which put the 
matter beyond all poflibility of a doubt; 
fo that I am inclined to think, either, that 
Dr. Pringle cut his pieces of flefh fo large 
that the lime-water could not penetrate 
them, or that his lime-water has been 
made from fhells, or chalk, not thoroughly 
calcined, which might have given the wa- 
ter a difagreeable fmell, that was miftaken 
for the putrid fcetor. 
EXPERIMENT 5. 
In order to fatisfy myfelf in regard to 
this matter, I put a bit of freih mutton, of 
two drachms weight, into an open glafs, 
containing fome ounces of lime-water: It 
was left there for a fortnight, and at the 
end of that time was found perfectly fweet; 
it had indeed grown quite tender, and 
when it it was cut into, and fome fpirit of 
vitriol dropt on it, an effervefcence en- 
fued, from the particles of the quick-lime, 
which had penetrated the fubftance of the 
flefh, and there being faturated with the 
fixed airt were now returned to their ori- 
ginal Hate of a calcareous earth. 120 
On the Respective 
This circumftance of the eftervefcence, 
will, if I miltake not, lead us to the true 
theory of the antifeptic power, and will 
fhew us on what it immediately depends. 
We have feen, by the iyth experiment 
of the preceding eflay, that putrefaction 
enfues in confequence of the efcape of the 
fixed air; therefore, whatfoever hath the 
power to refirain the flight of this element, 
or hinder the iutefiine motion, will prevent 
putrefaction. 
Calcareous earths, in their native 
ftate, have a ftrong affinity with fixed air, 
and we have feen, that upon this account, 
when they lie in contaCt with an animal 
fubftance, they attract fome of this ele- 
ment, and thereby accelerate putrefaction: 
For here they cannot penetrate the fubftance 
pf the putrefeent body ; they only fiurround 
it: But when thefe earths are calcined, 
a.nd converted into quick-lime, then a cer- 
tain portion of them is rendered fioluble in 
water ; the earthy particles, thus minutely 
divided, are now capable of pervading the 
foft texture of animal and vegetable bo- 
dies ; where, as hath been juft now feen, 
they immediately join themfelves to the 
fixed air of thofe bodies: So long therefore. Powers of Antiseptics. 
121 
as the particles of lime remain in this fitua- 
tion, fo long will the fixed air remain in a 
non-elaftic ftate, and fo long will the in- 
teftine motion, and that particular combi- 
nation of the infenfible parts which confti- 
tutes putrefa&ion, be kept at a diflance. 
All faline bodies * have a ftrong ajjinity 
with fixed air; and like wife refinous bodies •j* 
are moft tenacious offixed air, for they are 
only foluble in water when deprived there- 
of ; and hence the antifeptic virtue of all 
thefe fubftances; for they are all of them 
capable of fuch extremely minute divifion, 
that their particles can molt ealily pene- 
* “ For fince upon the difiolution of the conftitu- 
ent parts of fait by fire, it is found, upon feparating 
“ and volatilizing the acid fpirit, that the air-particles 
“ do in great abundance rufti forth from a fixed to an 
te e'laftic ftate, it muft needs be that thefe particles did, 
“ in their fixed ftate, attradf the acid fpirits.” Hales, 
vol. i. p. 294. 
See alfo Boerhaav. Elem. Chemite, tom. i. p. 531 ; 
where there are further proofs that falts have a very 
great affinity with, and are very tenacious of, fixed 
air. 
f That is to fay, completely foluble; fince we find 
that fome portion of the refinous part of vegetables dif- 
folves in water, by means of its ftri6l union with the 
gumrny or mucilaginous part.  On the Respective 
122 
trate into any animal, or vegetable body, 
and there, immediately join themfelves to 
the fixed air of thofe bodies, where remain- 
ing, they do, like the lime, when divided 
.and diffolved in water, keep back putre- 
faction by preventing the intefiine motion, 
and refir aming the flight of the fixed air. 
If we attend to all the methods that are 
ufed to prevent bodies from putrefaction 
and decay, we fhall find that they mofily 
tend to this fingle point : Timber is co- 
vered over with paint, or fome fuch unc- 
tuous and tenacious matter; fruit *, and 
other green vegetables, are preferved the 
year round, by flightly fcalding them 
(which thickens their external coats, natu- 
rally formed to prevent the efcape of their 
air) and then drying them well, and put- 
ting them into bottles clofely flopped the 
larger kind of feeds, fuch as chefnuts and 
acorns, have been preferved by Mr. John 
Ellis, found, and in a condition to grow, 
for nine months, by rendering their natu- 
ral, tough, and compaCt coverings, ftill 
more firm, from a thick coat of bees wax 
and fuet; flefh meat of all forts is preferved 
* Such as apples and goofeberries for baking. Powers of Antiseptics. 
123 
on the fame principle, and may be kept for 
many months, without much feafoning, 
provided it be well roafied or baked, and 
then covered over with lard, butter, or 
fuet; and eggs, it is well known, will re- 
main frefh for a long time, if their fhells 
be coated over with melted fuet, or the 
like tenacious fubfiance. 
Animal fluids, likewife, if the air is 
not fufFered to efcape from them, remain 
for a great while, without growing putrid; 
furgeons often meet with large colle&ions 
of extravafated blood, or ferum, which, 
after lying for years, in their own firm and 
compact cyfls, do not betray any thing 
putrid on their being firA let out; but in a 
very £hort time after the opening is made, 
and there is a way for the air to fly off, the 
difcharge grows intolerably fetid; and we 
alfo find, where wounds are made in flefliy 
parts by Ample incifion, and are fo circum- 
Aanced as to lay under no neceflity for fre- 
quent dreffing, that, when carefully kept 
covered, and the efcape of the air prevent- 
ed, they heal in a very fliort time, without 
any fign of fuppuration, which is a certain 
degree of putrefaction. 124 
On the Respective 
The principle upon which ajlringents 
become antifeptics is eafily comprehended. 
The aCtion of ajlringents confifts in their 
corrugating, or crifping up the animal 
fibres, whence the folid particles of thefe 
fibres are brought to a nearer approach, 
and the power of their cohefion confidera- 
bly increafedj confequently, the fubftance 
of the body, fo aCted upon, mufl become 
more firm, and compaCt, and this of courfe 
mufl hinder the intejline motion, without 
which there can be no putrefaction. 
All bodies polTefied of this afiringent 
power, writh regard to thefibres, and which, 
at the fame time, have a lfrong ajfinity 
with watery mufl be antifeptics on a dou- 
ble account j accordingly, w'e fee whence 
it arites, that ardent fpirits, and the ftrong 
mineral acidsy efpecially the vitriolic, refill 
putrefadtion fo very powerfully : For thefe 
not only abforb the water from the putref- 
cent fubltance, but likewife crifp up its 
fibres, and thereby render it fo hard and 
durable, that no change of combination 
will take place for many years. 
So far in relation to the virtue of things 
oppofing putrefaction, let us now proceed 
to confider thole which have the power of Powers of Antiseptics. 
refloring fweetnefs to fubftances actually pu- 
trid. 
EXPERIMENT 6. 
Having put a number of fmall pieces 
of mutton into a phial with water, and 
placed it in a moderate degree of heat, in 
order to make them putrefy the fooner, I 
found them, after ftanding four days, fuf- 
ficiently foft and putrid ; I then put Jive of 
thefe bits of putrid mutton into as many 
cups, and poured, on the firft, fpirit ofvi- 
triol} on the 2d, fpirit oj' fea-Jalty on the 
3d, vinegar ; and on the 4th, frejh lemon- 
juice ; the 5th cup contained only water,, 
and was left as a ftandard, by which the 
others were to be compared *. 
To have a fynoptical view of the changes 
from day to day, I formed the annexed ta- 
ble, No. 5, and at the expiration of twen- 
ty-four hours, found the feveral appear- 
ances exa&ly as fet down in the firft co- 
lumn thereof; after forty-eight hours, the 
appearances were agreeable to the fecond 
* The mineral acids in this experiment were diluted 
fo as to reduce them, as nearly as could be judged, to 
the ftrength of the vinegar that was ufed. 126 
On the Respective 
Acids of 
24 Hours. 
48 Hours. 
3 Days. 
4 Days. 
Vitriol. 
The bit of putrid 
flefh was found hard, 
fhrivelled up, and al- 
moft fweet. 
Entirely fweet; very 
much lhrivelled and 
hardened. 
As on the day be- 
fore. 
As on the day be- 
fore. 
Sea-falt. 
Not fo much hard- 
ened as in the Sp. 
Vitrioli, nor fo much 
fweetened. 
More fweet than on 
the preceding day, 
but not entirely 
fweet. 
No change fince yef- 
terday. 
Putrid fmell return- 
ed. 
Vinegar. 
Softened ; greatly 
fwelled, and entire- 
ly fweet. 
No change fince yef- 
terday. 
No change. 
Grown livid, but 
ftill foft and fweet. 
Lemon- 
juice. 
Softened j greatly 
fwelled, and entire- 
ly fweet. 
No change fince yef- 
terday. 
No change. 
Grown perfectly 
white, but quite 
fweet. 
Table V. Acids tried as Correctors of Putrefaction. Powers of Antiseptics. 
column of the table; at the end of threer 
days, things flood as in the third; and af- 
ter four days, the feveral bits of the mut- 
ton were found in the condition expreffed 
in the fourth column. 
Being thus fatisfied of the power of 
acids to corrett putrefaction, I threw out all 
the pieces of the mutton but the 5th, 
which had ferved for a ftandard; referving 
it for another experiment. 
Thus it appears, that the 'vitriolic acid 
has a more powerful antifeptic virtue than 
the marine y and that both of them flrew 
an ajtringent quality, by their hardening 
animal fibres, though in a different degree; 
and the effeCt of the vegetable acids, in fo 
remarkably foftening and relaxing the folid 
fibres, gives room to expeCt great things 
from their power as refolvents, when out- 
wardly applied. 
Since acids both rejift and corrett putre- 
faction, it was very reafonable to expeCt 
that all putrid difeafes fhould yield to them,, 
when given in the way of medicine; but 
experience, the only thing on which the 
jbrattice of phyfic mufl always reft, abun- 
dantly fhews that their power in this re- 
fpeCt is pretty much limited 5 and that 
1  On the Respective 
where the putrid matter to be corrected 
lies beyond the firfl pafiages, acids are 
found quite infufficient to conquer it. 
EXPERIMENT 7. 
But the ale aline falts even exceed the 
acids, in regard to the power of correcting 
putrefaction ; for two fmall pieces of pu- 
trid beef, after lying a night in the volatile 
alcali*, diluted with water, in the propor- 
tion of four of the latter to one of the for- 
mer, were found perfectly free from the 
putrid flench; but they were fo fully 
charged with the liquors in which they 
had lain, that not even boiling could de- 
flroy the peculiar fmell of the volatile al- 
cali. 
EXPERIMENT 8. 
The fixed, alcali like wife fweetens very 
powerfully: A little bit of putrid beef, 
from lying twenty-four hours in lixivium 
tartari, diluted with an equal quantity of 
water, became hard and firm, and was 
* Both the mild and the cauftic alcalies were tried ; 
viz. Spiritus cornu cervi per fe, & Spiritus falis com- 
moniaci cum calce viva. Powers of Antiseptics. 
129 
found to have no fmell, but that which is 
peculiar to the lixivium. 
EXPERIMENT 9. 
But the neutral mixture does not give 
fweetnefs : Spiritus mindererl, if made in 
fuch manner as to be perfettly neutral, 
feems to have no power to correct putre- 
faction ; if the volatile alcali is allowed to 
predominate, the mixture will fweeten in 
proportion, for, as hath been juft now re- 
lated, the volatile alcali is very powerful in 
driving off the putrid flench. 
EXPERIMENT io. 
Spirit of vitriol and lixivium t art ari be- 
ing mixed to the point of faturation, and 
a bit of putrid beef being left in the liquor 
for twenty-four hours, was found not at 
all fweetened. 
EXPERIMENT II. 
A strong decoCtion was prepared, 
from equal parts, tormentill root, balauf- 
tines, pomegranate peel, and red rofes, and a 
bit of putrid beef was immerfed in the li- 
quor; the fcztor feemed yather increafed 130 
On the Respective 
than diminifhed, by lying twenty “-four 
hours in this deco&ion. 
EXPERIMENT 12. 
The fame thing happened with lime- 
water, which, notwithftanding it rejijls 
putrefadlion fo ftrongly, appears to have no 
power to cor reft it. 
EXPERIMENT i3. 
Neither have ardent fpirits the leafl 
power to deflroy the putrid flench, any 
further than as it is, in fome degree, ob- 
fcured by their own peculiar flavour. 
EXPERIMENT 14. 
Strong decodlions of the bark, and of 
valerian, together with flrong infuflon of 
chamomile flowers, were alfo tried as fweet- 
eners. After fuffering three fmall pieces of 
putrid flefh to lie thirty-flx hours in thefe 
liquors, I could fcarcely take upon me to 
fay they were fweetened; the putrid flench 
ind'eed was rendered more tolerable, by 
the fmell of the liquors, but did not feem 
to be much conquered. 
For unlefs the decodlions be frequently 
renewed, as- was- done by Dr, Pringle, fo Powers of Antiseptics. 
131 
ts by repeated affufions the vifcid particles 
of the gum-refin may be applied in fuch 
quantity as will wholly entangle and fix 
the volatile particles of the putrid alcali9 
the effeCt is but fmall; excepting the pu- 
trid body is allowed to remain long enough 
in the decoCtion or infufion for a ferment a 
tion to begin, which will indeed effectu- 
ally change the flate of the mixture, and 
produce fuch a new combination as will 
maintain its fweetnefs for a confiderable 
length of time. 
This power of fermenting mixtures to 
ref ore fweetnefs was difcovered by Dr. 
Pringle j but as I have made feveral expe- 
riments in relation thereto, I fhall here lay 
them before the reader. 
EXPERIMENT 15. 
While the 6th experiment* with re- 
gard to the power of acids in correcting 
putrefaction, was going on, I one evening 
took a bit of the mutton out of the fore 
phial\ which was grown, by that time, ex- 
ceedingly foft and putrid* and having 
faftened it to a thread, immerfed it, at 
eight o’clock, in a vat of melaffes wajhi at 
the diftillers, then in a degree of fermen-  On the Respective 
tation, rather upon the decline. Next 
day at noon, I took it out, and having 
wafhed it in water, in order to free it from 
the fmell of the liquor in which it had been 
lying, found it perfectly fweet and firm. 
As this piece had been rendered fo in- 
tirely fweet and firm, and, to all appear- 
ance, found, for it looked like a bit of 
meat that had been flightly fried, I con- 
jectured that it might not be necefiary for 
it to lye fo long as fixteen hours y I there- 
fore obtained a gallon of the wafh from my 
friend the difliller, that I might examine 
the progrefs at home, and at my leifure.. 
EXPERIMENT 16. 
I plunged into this gallon of fermenting 
liquor the very identical piece of mutton 
that had ferved as a ftandard in- the 6th 
experiment, on the acids; and which, 
from lying in an open cup for feveral days, 
was grown fo foft that I was obliged to tie 
it round with a piece of thread, (for, when 
the thread was palled through it, the flefta 
was fo tender that it would not hold) and! 
fo extremely putrid that the flench was in- 
tolerable,. Powers of Antiseptics. 
133 
In one hour the putrid fmell was much 
abated, and at the end offive entirely gone, 
the meat being now firm, and perfectly 
fweet; it was hung up in the open air, 
where it foon became dry, and remained 
fweet ever after. 
EXPERIMENT 17. 
In order to fee whether this change de- 
pended on the liquor, or on the vapour, I 
fufpended a thin bit of putrid mutton, from 
the Jiore phialy in the mouth of the vefiel 
wherein the wajh was fermenting, but fo 
as not to touch the liquor* and left it there 
-during the night; in the morning it was 
found plumped up, fweet, and firm. 
This experiment I frequently repeated, 
and always with fuccefs; but whoever 
chufes to try it* mud: take care that the 
pieces of putrid meat be cut thin, fo as the 
vapour may have power to pervade them, 
otherwife the fweetnefs will not be com- 
pletely reftored; whereas, when the expe- 
riment is made with the liquor, and the 
pieces of putrid belli are fufifered to lie 
foaking in it, they may then be cut of any 
fize that the party pleafes; for if time be  On the Respective 
given, the fubtile gas will penetrate, and 
produce its eftedt. 
EXPERIMENT 18. 
Even acids will fweeten pretty large 
pieces two bits of putrid beef, of an 
ounce weight, were left feverally in di- 
Jlilled vinegar, and in melajfes wajh, juft as 
it had done working. 
The firft was found very much, though 
not entirely, fweetened, after lying twenty- 
four hours ; but the lecond was rendered 
perfe&ly fweet. In order to fee if they 
were thoroughly penetrated, and fweetened 
to the heart, I boiled both the pieces, and 
was furpri?;ed to fee the one which had 
lain in the acid go all to pieces in the boil- 
ing, which I thought the more odd, as it 
had been rendered hard and firm; an ef- 
fect wherein the dijiilled vinegar differs 
widely from that which is not diftilled. 
This diffolution I aferibed to the peculiar 
dijfolvent quality of the vinegar, and did 
not believe, until I tried it, that a mineral 
feid yyould produce the fame effect. Powers of Antiseptics. 
135 
EXPERIMENT 19. 
But an ounce of putrid beef, after ly- 
ing twenty-four hours in dilute fipir it of vi- 
triol, and coming out perfectly hard, fweet, 
and contracted, upon being boiled, fell all 
to pieces, exadtly as did the one which had 
lain in the diftilled vinegar; and when 
rubbed between the fingers, it melted away 
like fo much wet pafte. To be certain 
that nothing of this was owing to too 
much boiling, I put a little bit of beef, of 
a drachm weight, that had been fweetened 
by the volatile alcali, into the veffel along 
with it, and fuffered it to remain the whole 
time of the boiling ; but it came out white 
and firm, and, as hath been mentioned al- 
ready, firong of the volatile alcali. 
For the alcalies cannot be faid, withpro* 
priety, to rejlore fweetnefs; they only drive 
off a weaker alcali: As the fixed alcali can 
difpofiels the volatile, fo both of them have 
the power to drive off the firnple putrid al- 
cali ; and thus the putrid fubftanee be- 
comes the bafis of afironger, inftead of a 
Weaker, alcali*. 
* See the 27th, 29th, 31ft, and 32d experiments of 
$he preceding eflay.  On the Respective 
The manner in which acids fweeten pu- 
trid flefh feems alfo pretty plain ,* for their 
adtion appears to confifl in faturaiing and 
fixing the putrid alcali, and by thus deflroy- 
jng its volatility, they hinder the putrid 
factor from flying off, and flriking the or- 
gans of fmell ; but at the fame time that 
acids do this, they diffolve the elementary 
earth, and thus deftroy the texture of that 
fubflance whofe foundnefs they were fup- 
pofed to reflore. Whereas, the peculiar 
excellence of the fermenting liquors is, to 
reflore fweetnefs to the fluids, and firmnefs 
to the folids. 
EXPERIMENT 20. 
Two pieces of linnen rag were dipt in 
the putrid liquor of the jiore phial, one 
was fufpended oyer the rwajh in fermenta- 
tion, and thp other was hung qp in the 
ppen air. In two hours the one expofed 
to the vapour became almpft fweet, the 
Other remaining as offenfive as at firfl; and 
jn fix hours, the firfl piece of rag had no 
fmell but that pf the vapour; while the 
Other, though now grown dry, flill flrongly 
fetained the putrid flench. Powers of Antiseptics. 
137 
As fugar is an antifeptic, in confequence 
of its faline nature, I did not know but 
fomewhat of the virtue of the melaJJ'es waft) 
might depend on this circumftance. 
In order to determine this, I immerged 
one fmall bit of putrid flefti in a mixture of 
bread an,d mutton, with lemon-juice, and 
fufpended another in the neck of a phial 
containing a fermenting mixture, with 
fpinnage; and found, after eight hours, 
that both of them had loft the putrid 
ftench, and had now no other fmell than 
that of the mixtures; which, as hath been 
elfewhere obferved, was fweetifh, and not 
unlike fenugreek feed. The like experi- 
ment was tried with another fermenting 
mixture, as the reader will find by turning 
back to the 47th page. 
Dr. Pringle feems to think, that the pu- 
trid fmell in thefe mixtures is deftroyed by 
the acid which is produced in the courfe of 
the fermentation. Relying on his authori- 
ty, I was for fome time of the fame opi- 
nion, and looked on the fuhtile gas as 
fomewhat of the nature of a volatile acid; 
for I had then the ideas of acid and antifep- 
tic ftrongly connected together in my  On the Respective 
mind : but, upon enquiry, this notion was 
found to be void of foundation. 
EXPERIMENT 21. 
For one piece of linnen rag dipped in 
lixivium tartari, and another tinged blue\sy 
the fcrapings of rhadijhes, were expofed for 
eight and forty hours to the vapour arifing 
from a large vat full of melaffes wafh, in 
high fermentation j yet the firft was not at 
aft faturated, nor the laft in any, even the 
flighted; degree, changed red. 
And in all the fermenting mixtures that 
I tried, none of them became four, ex- 
cepting one (No. 6, table i), for feveral 
days after the firft ftage of the fermentation 
had ceafed *. 
* In order to fee how long thefe kind of mixtures 
would preferve their fweetnefs, I referved three of the 
14th experiment of the fecond effay; to wit, thofe with 
the barley, the rice, and the oats. 
Into the phial with the barley I put about half an 
inch of a thread which had been dipped in a putrid 
animal fluid; into the one with the rice I poured a tea- 
fpoonful of- vinegar ; the third, with the oats, was left 
without any addition. 
All the three mixtures were now at reft, having run 
through their firft ftage, and being every one perfe&ly Powers of Antiseptics. 
139 
EXPERIMENT 22. 
Two drachms of the cortex in powder, 
and half an ounce of faliva, were added 
to a mixture of ox-gall and water, which 
was grown putrid, for it had been ufed 
fweet, they were left in the common temperature of the 
air; the phials not clofely ftopt. (This was in the 
month of July-) 
For three weeks, r>o alteration was perceivable in 
any of them ; but at the end of that time, the mixture 
into which the putrid ferment had been put began the 
inteftine motion, which continued, in a gentle degree, 
for feven or eight days before the mixture became fully 
putrid. 
The phial into which the vinegar had been thrown, 
began, at the three weeks end, to (hew fome fmall 
figns of inteftine motion ; a thick, white fcum formed 
on the furface, and it did not grow putrid until it had 
(food, in all, fix weeks. 
The third mixture, to which nothing had beed add- 
ed, remained quite at reft, without (hewing any figns 
of motion for two months ; then it was found to have 
grown four, and had contracted acidity fufficient to cur- 
dle milk, and to raife an ebullition when fome fait of 
hartfhorn was thrown into the phial. 
I now corked the phial, and fet it afide for three 
months; and then, having diftilled the mixture by a 
very gentle heat, I obtained a volatile alcaline fpirit, of 
a peculiar fmell, not unlike that obtained from the pu- 
trid blood formerly mentioned. 140 
On the Respective 
as a ftandard to two mixtures of gall and 
tejiacea. 
Upon the firft mixture, the fcetor in- 
creafed greatly, and the bark feemed to a& 
on the putrid bile in a manner not unlike 
the action of lime, or fixed alcali, when 
mixed with crudefal ammoniac, in order to 
drive off the volatile akali. 
The mixture was now laid by for twen- 
ty-four hours, at the expiration of which 
I found the putrid fmeil much abated, 
and a fermentation beginning \ I now fuf- 
pended a little bit of putrid fiefh in the 
neck of the phial, and placed it in a mo- 
derate degree of heat. When twenty-four 
hours more were elapfed, | again exa- 
mined the mixture, which was dill in 
brifk motion, and found that it had en- 
tirely loft the fcetor, having now acquired 
a new and peculiar fmeil, which was not 
only fweet, but agreeable, and different 
from the original fmeil, either of frefh 
bile, or of the cortex. 
The bit of putrid flefh was found fweet- 
ened; having removed it, I fixed the 
bended glafs tube as defcribed formerly, 
and, by means thereof, joined a fmall phi- 
al, containing a drachm of non-effervefcent, Powers of Antiseptics. 
141 
volatile alcaline fpirit, to the phial which 
held the fermenting mixture : They were 
left in conjunction for twenty-four hours, 
and when feparated, fome Jpirit of vitriol 
being dropped into the fmall phial, raifed 
a fmart ebullition. 
It has been fhewn in former experi- 
ments, how readily the bark runs into fer- 
mentation out of the body,, and it was then 
hinted, that there is great reafon to expeCt 
that it will be ft ill more prone to ferment 
in the body, when opened by the digeftive 
fluids and the prefent experiment thews 
plainly, that when opened by fermenta- 
tion, the cortex, like the melajj'es, and 
other things that were tried, gives out 
fome fubtile matter, which hath the power 
of refloring fweetnefs to putrid animal fub- 
ftances: Is it not agreeable, then, to rea- 
fon as well as experiment, to account for 
its antifeptic virtue upon this principle ? 
If we attend to the nature of the dif- 
cafes wherein the bark is found moft ufe- 
ful; and, on the other hand, Femark thofe 
cafes wherein it either does harm, or 
proves of no effeCt, we fhall find fome 
ground for eftablifhing this hypothecs.  On the Respective 
142 
First, the cortex is of the highefl fer- 
vice in gangrenes, where the veflels are re- 
laxed, and the blood diflolved ; 2, in 
wounds and ulcers, where the folids and 
fluids are in the fame weak and diflolved 
ftate; 3, in the low ftate of malignant fe- 
vers, and fmall-pox, where the humour? 
are evidently putrid ; 4, in intermittent 
fevers, where almofl: every fymptom be- 
trays evident marks of a putrefadlive acri- 
mony. 
In thefe lafl it feems to be the molt 
plaufible opinion, that the caufe is feated 
originally in the flexure of the duode- 
num *; here the cortex comes into imme- 
diate contadl with the putrefadlive collu- 
*uiesl and prefently -f* running into fermen- 
tation, foon throws off a quantity of the 
fubtile vapour, fuflicient to faturate the 
acrimonious matter which being thus 
* See Hoffman, in the chapter de confenfu par hum ner- 
vofarum generatim iff figillatim cunt ventriculo. Pringle, 
p. 330. And Cleghorn's Difcafes of Minorca, p. 161 iff 
183. 
f The putrid matter will encreafe the tendency to 
putrefaction. Thus we fee how well it is adapted to 
work out its own cure, provided it be fupplied with pro* 
per materials. Powers of Antiseptics. 
143 
rendered mild and fweet, the febrile coin- 
motion, which would have enfued had thi3 
irritating caufe not been reifioved or cor- 
rected, is now prevented. 
In this cafe, we have fuppofed the ge- 
neral mafs of fluids to be untainted ; but, 
even in cafes where the putrefactive acrb 
mony has made further advances, and has 
actually taken plaice in the conffitution, if 
the medicine be continued, and given in 
large quantities, its falutary effects will 
prefently appear, and will fhew that the 
antifeptic vapour can reach the blood, and 
there reflore its confluence, and correCt its 
fharpnefs. 
But this valuable drug has another 
great advantage. Befide its readinefs to 
ferment, and being able to yield a large 
proportion of the antifeptic vapour, it hath 
alfo a remarkable power of bracing up and 
ffrengthening the vafcular fyflem; thus 
enabling the powers of the body to con- 
coCt the morbific matter, and expel it by 
the proper emunClories : For it is obferv- 
able, that, after a liberal ufe of it,'pro- 
fufe evacuations of urine and fweat often 
enfue, and fometimes beneficial difcharges 
by fiool; then, when the offending mat- 144 
On the Respective 
ter is fo thrown off or corrected, the affric- 
tive quality of the bark braceth up and 
ffrengthens the folid fibres, which had 
been relaxed and weakened by the putre-* 
fadtive acrimony. 
But in difeafes where there is an in- 
flammatory tendency, where the veffels 
are full, the fibres tenfe and rigid, and the 
blood thick and fizey, then is the bark 
hurtful and dangerous 3 becaufe, it throws 
much air, and no water, into the blood, 
and confequently muff highly increafe the 
morbid difpofition of the fluids, while, at 
the fame time, its affringent virtue muff 
add to the tenfion of the living fo lids* 
For this fubtile a?itifeptic vapour appears 
to confift chiefly, if not altogether, of the 
fixed air of the fermenting fubftances3 
fince I have found, by experiment, that as 
as the fixed air thrown off by efi'ervefcence 
agrees with the gas fylvefire, in fufi'ocating 
animals, fo does it agree with the fame gas, 
in the property of refioring fiweetnefs. 
EXPERIMENT 23. 
A small piece of putrid beef, taken 
immediately from the liquor in which it 
lay, was put into a cup with fome lixivium Powers of Antiseptics. 
fartari, and on it was poured by degrees, 
a fufficient quantity offpirit of vitriol't 
The moment the faturation was com- 
plete, the bit of beef was taken out, and 
found to have almoft entirely loft the pu- 
trid foetor what ftnell it now had, was 
rather to be termed mufty than putrid; on 
wafhing it in clean water, this mufty lmell 
went off, and a very little of the putrid 
was again to be perceived. 
EXPERIMENT 24. 
Another bit of the fame putrid beef 
was put into a cup, with fome fait of 
hartfliorn, and on them vinegar was pour- 
ed, to the point of faturation: Immediately 
on the celfation of the ebullition, the piece 
of flefli was taken out, and found to have 
entirely loft th ofoetor, having now no fmell 
but that of the neutral mixture, which is 
not unlike the fmell of burnt horn; but 
upon wafhing the beef, this fmell went off 
in great meafure, and not the lead of the 
putrid dench was to be perceived. This 
bit of beef was much fofter than the one 
in the foregoing experiment, where the 
edervefcence was not near fo violent, and 
did not lad fo long, as in this prefent mix- 146 
On the Respective 
ture; and hence I concluded, that this lad: 
piece of the putrid flefh was fo much 
more fweetened, becaufe of its having an 
opportunity to abforb a much greater quan- 
tity of air than the other one had. 
Both thefe pieces were boiled, and 
both came out perfe&ly firm; the lafl 
piece, upon being cut into, was found 
fweet to the very heart ; but the other was 
found not to have been fo thoroughly per- 
vaded, as it difcovered a little of the putrid 
fmell on being divided. 
EXPERIMENT 25. 
A bit of putrid flefh, of about a drachm, 
was put into the phial C, as in figure 11, 
which previoufly had a drachm or two of 
fal cornu cervi thrown into it, the glafs 
tube was fixed clofely into the neck of the 
phial, and the other extremity of the tube 
inferted into a fmall phial, with half a 
drachm of the putrid liquor that lay about 
the rotten flefh j vinegar was now poured 
through the funnel, to raife an ebullition. 
When the fait was all diffolved, and the ef- 
fervefcence at an end, the phials were fe- 
parated; the bit of beef was now found 
fweet, and the putrid liquor, which be- Powers of Antiseptics. 
fore fhewed no figns of ebullition upon 
dropping an acid into it, now effervefced 
plainly, on the addition of fpirit of vitriol $ 
and it had befides loft much of the putrid 
foetGr, 
And thus we fee, that fermenting and 
effervefcent mixtures are the moft power- 
ful of all known antifeptics. 
Some fhare of this pov/er remains in li- 
quors after they have run through their 
firft ftage of fermentation, which is differ- 
ent in different liquors; as may be feen in 
the annexed table (No. 6), and feems to 
depend on the quantity of the fubtile va- 
pour which is left in the liquor, lince thofe 
that are moft fparkling and bride, are 
found to poffefs the greateft diare of anti- 
feptic power*. 
The fixed air, when transferred from a 
found body into one that is putrid, appears 
* <c When, by fermentation, the cpnftituent parts 
<£ of a vegetable are feparated, part of the air flies off 
tc into an elaftic ftate ; part unites with the fait, oil, 
i( and earth, which conftitute the tartar; the remain- 
“ der, which continues in the fermented liquor, is 
“ there, fome of it in a fixed, and fome of it in an 
elaftic ftate.” Hales, vol. i. p. 300. 148 
On the Respective 
Table VI. Common Fermented Liqjjors tried as Sweeteners of 
Putrid Flefh. 
Claret. 
Lifbon White 
Wine. 
Englifh Cyder, 
(bottled.) 
Common Dub- 
lin Ale. 
MelaflesWafh, 
(newly fer- 
mented.) 
Sugar and Wa- 
ter, (not fer- 
mented.) 
At the end of 
30 hours, the 
bit of put. id 
meat was found 
perfectly fweet 
and firm. 
At the end of 
12 hours, the 
bit of meat was 
found perfectly 
fweet. 
At the end of 8 
hours, the bit 
of meat was 
found quite 
fweet. 
After 24 hours, 
not at all fweet- 
ened. 
N.B. This 
kind of ale is 
but of the 
weaker fort, 
and generally 
not very brilk. 
In 12 hours, 
the bit of putrid 
meat became 
perfectly fweet. 
After 24 hours, 
not at all fwcet- 
ened. Powers of Antiseptics. 
149 
to reftore to that body the principle that 
had been deftroyed or loft *. 
But here it may be demanded, what 
can thefe experiments prove with regard to 
the reftoration of putrid fluids, in a living 
body; is it poffible to faturate thefe hu- 
mours with fuch a quantity of air as will 
be fufficient to correcl their fharpnefs, re- 
Jiore their conJiftencey and bring back their 
fweetnefs ? 
To this it may with fafety- be replied, 
that it is not only poffible, but that it is, 
perhaps, the only way by which this 
change can be produced. 
For we have feen that there is a decep-* 
tion, in regard to both acids and alcalies, 
when we fuppofe them to reftore fweet- 
nefs to a putrid animal fubftance ; that the 
JirJl, fo far from giving foundnefs to fuch 
kind of fubftances, do in reality deftroy 
their texture; and that the fecond only 
change the nature, but do not reftore the 
original fweetnefs. 
* The manner of afting of air, when transferred 
into a body whofe texture is broken and diffolved, will 
be better comprehended from fome experiments here- 
after to be mentioned in the 5th Eflay ; the thing be- 
ing, in fome degree, rendered vifible. 150 
On the Respective 
But acids, we have likewife feen, are 
neutralized*, during the alimentary fer- 
mentation, and therefore they cannot ad 
as acids, by faturating any thing of the <2/- 
calious kind that they meet with in their 
courfe of circulation. The power of acids 
therefore, is confined; and we are not to 
exped, that they are to pervade the mi- 
nute branches of the vafcular fyftem ; in- 
deed, it is evident, that they ought not to 
be allowed to pafs into the blood in their 
acid form, fince it is plain, that, from their 
diflolvent nature, the body mull be de- 
ftroyed, and its moil folid parts melted 
down to a jelly, if naked acids were to be 
received into the general mafs of fluids 
Their adion, therefore, cannot extend be- 
yond the limits of the alimentary canal, 
where they may come into contad with, 
and corred the fharpnefs of a putrid collu- 
vies. In thefe cafes they may, and ac- 
tually do, exert very notable powers, as is 
* See the 3d and 5th experiments of the 2d Eflay. 
f In thofe deplorable cafes that now and then hap- 
pen, where all the bones become foft, a manifeft aci- 
dity hath been difcovered in the fluids; a thing never 
obferved in other morbid cafes. See Haller. Element. 
Phyfiolog. tom. ii. p. 94. Powers of Antiseptics. 
-often experienced, by their preventing 
licknefs and naufea, and retraining vomit- 
ings 3 and by neutralizing, as it may be 
termed, the putrefactive matter, thus pre- 
vent it from carrying into the blood its pe- 
culiar deftru&ive quality. 
It is a point not yet thoroughly fettled, 
whether alcdies do in reality promote pu- 
trefaction in thing bodies 3 there can be no 
doubt of their power to refill and correct 
putrefaction, in dead bodies 3 but whether, 
upon the prefumption of this virtue, they 
can be given with propriety, as antifeptics, 
is not fo clear. 
A very eminent and fuccefsful practi- 
tioner is of opinion, ** That the exhibition 
“ of volatile alcalious falts to the lick, in 
“ putrid difeafes, is adding fuel to the fire 3 
** for they certainly diffolve or break the 
“ globules of the blood, and thence more 
“ fpeedily bring on the general putrefac- 
*( tion.” And he relates a fingular cafe, 
where an uncommon quantity of fait of 
hartjhorn being taken by a young gentle- 
man, and the ufe of it continued, An 
*c heCtic fever enfued, as alfo vaft hoemor- 
rhages from the inteftines, nofe, and 
fe gums 3 every one of the teeth dropped  On the Respective 
out, and the patient could eat nothing 
“ folid ; he wafted vaftly in his flefh, and 
“ his mufcles became as foft and flabby as 
“ thofe of a new-born infant; and broke 
“ out all over his body in puftules, which 
“ itched moft intolerably, fo that he 
tf fcratched himfelf continually, and tore 
“ his fldn with his nails in a very fhock- 
“ ing manner ; his urine was always excef- 
<c flvely high-coloured, and very foetid *.’* 
Astringents, as hath been fhewn, 
prevent putrefaction very powerfully, but 
we find that they have not the leaft degree 
of power to correct it. 
But putrefactive acrimony firft takes 
place in the fluids, and it is on account of 
their indifpofition, and the deftruCtive and 
* Huxham on the Sore Throat, p. 67 5c 68. The acri- 
Hiony in this cafe, however, appears to have been what 
Gaubius terms, “ Acre alcalefccns volatilepurum which, 
though a component part, is not to be confounded, or 
looked on as the fame, with the real and genuine pu- 
trid acrimony. 
Gaubii Init. Patholog. fe£t. 310 5c 312. Putrid acri- 
ipony feems to confift in an ov,er-proportion and irre- 
gular combination of the faline and phlogiftick or oily 
particles of the blood ; thefe particles being left at li- 
berty to run into this deftru&ive combination from the 
want of their bond of union, the fixed air. Powers of Antiseptics. 
153 
irregular combination of their particles, 
that the texture of the folidfibres is weak- 
ened, and their cohefion impaired; there- 
fore, bracing up and ftrenghtening the fy- 
flem of folids, while the mafs of fluids 
continues in the morbid ftate, can avail 
nothing; it is beginning the cure where it 
ought to be concluded. 
Astringents, therefore, as antifeptics, 
can only be of importance in thofe cafes, 
where, from extreme relaxation and refo- 
lution of the folids, the diflolved fluids are 
fuffered to tranfude, and either form fpots 
of different hues, or run off by adtual 
haemorrhage 5 here indeed, the acid ot vi- 
triol, as an afiringent, not as an acid (for 
vinegar would do nothing in this cafe) is 
found of great ufe, in gaining time', either, 
till the powers of the animal ceconomy 
correct the morbid difpofition of the fluids, 
or that the fame thing is brought about by 
the virtue of fome efficacious a?itifieptics, 
fuch as the cortex, which is the thing ufu- 
ally joined with the fpirit of vitriol, and 
that with the greatefl propriety, on ac- 
count of its own aftridtive quality, as well 
as extreme readinefs to run into fermenta-  On the Respective 
tion; which is the circumftance that con- 
ditutes a true and genuine antifeptic. 
The phyfician who gives aftringents in 
thefe cafes, and with thefe views, ads not 
unlike a furgeon who fecures and ties the 
blood-vefiels that are divided in the begin- 
ning of an operation, in order to allow 
himfelf fufficient time to finilh it with 
fafety and regularity. 
Indeed, the credit that adds have 
gained as antifeptics, hath refted much on 
the fuccefs that has attended their exhibi- 
tion in the circumftances above-mention- 
ed s but that they ad: in thefe cafes as 
mere aftringents, may be found from a 
clofe attention to the progrefs of the cure. 
Let any one read the very remarkable 
cafe in Dr. Huxhanis Treatife on Fevers, 
(p. 62) and it will plainly appear that the 
add of the vitriol braced up the fibres, 
checked the tranfudation of the diflolved 
blood, and thus obtained a truce until the 
repeated dofes of the cortex. “ The rice, 
“ the panadoy the /ago, the hart floor n-jelly, 
“ well acidulated, and the toajl out of cla- 
“ ret and red port wine,” generated enough 
of the antifeptic vapour to faturate and Powers of Antiseptics, 
155 
correct, in fome degree, the putrefactive 
acrimony, whereby the patient was ena- 
bled to get upon his legs, when exercife, 
and a proper diet, reftored him to his per- 
fect health *. 
And to fhew this flill further, in a cafe 
no lefs deplorable, I lhall give the follow- 
ing, communicated by Dr. Archer, phyli- 
cian to Stevens’s Hofpital in Dublin. 
THOMAS BROWN, a robuft coun- 
tryman, of about twenty-four years of 
age, was admitted, the firfl of February, 
1762, a furgical patient into Dr. Stevens’s 
Hofpital, for an Herpes exedens, which ex- 
tended from the nape of the neck to the 
inferior part of both fcapulee. After hav- 
ing been purged, on the 5th he was or- 
dered to take ten grains of the blue pill 
every day, which he did until the 25th fo 
that in this time he had taken near two 
hundred grains of mercury, without any 
appearance of falivation -J-. 
* There is a cafe in Sydenham equally ftrong in re- 
gard to this point; it was communicated by Dr. Good- 
all, and is to be found in the Letter to Dr. Cole, con- 
cerning the fmall-pox and hyfteric difeafes. 
f This blue pill ufed in Stevens’s hofpital confifts of 156 
On the Respective 
On the 26th, he complained of ficknefs 
in his llomach, entire lofs of appetite, and 
great wearinefs; the ulcer had not mend- 
ed ; he was therefore confined to his bed, 
and ordered to drink plentifully of warm 
diluting liquors. The 27th, there ap- 
peared numerous petechice on his whole 
body. The 28th, the number of thefe in- 
creafed, and appeared livid. The 1 fit of 
March, he had a haemorrhage from the 
nofe, which was attempted to be ftopt by 
different ftyptics ; but thefe caufing him 
to fneeze, rather increafed the bleeding : 
The fame evening he was ordered a vo- 
mit, which he took, and another next 
morning j by thefe the bleeding likewife 
encreafed. 
The apothecary of the houfe (it not 
being the phyficians’ vifiting-day) then 
ordered him three fpoonfuls of the fol- 
lowing mixture, to be taken every two 
hours. 
fy. Aq. Menth. vul. Sim. Tin Si. Rofar. cum 
triplici quant. Elix. Vitriol. Acid, aa un- 
cias tres TinSi. Cort. Peruv. uncias duas. 
nothing but crude mercury, and as much Venice tur- 
pentine as is fufficient to extinguish the quickfilver. Powers of Antiseptics. 
157 
Tinfit. Martis in Sp. Satis, Sefcunciam 
M. 
This, he faid, retrained the hsemor- 
rhage ; but, on the 3d, blood came away 
abundantly in his urine. 
He continued the above mixture until 
the 4th, when I was defired to fee him : 
I found him greatly exhaufted, his pulfe 
quick and weak, frequently fpitting black 
coagulated blood, his urine the colour of 
blood, his body thickly covered over with 
petechice, red and livid, which here and 
there ran into vibices, as if he had been fe- 
verely Scourged. 
I ordered him to take a drachm of 
the cortex every hour, wafhing it down 
with four ounces of the infufum amanim 
of the London difpenfatory, with thirty 
drops of the acid elixir of vitriol in each 
dofe. 
After taking a few dofes, he imagined 
himfelf better and therefore, of his own 
accord, took it every half hour. The 7th, 
the blood difappeared from his urine, and 
greatly abated from his mouth and nofe ; 
the livid petechice changed to red, and the 
vibices into diftindt petechice, The 11 th, 
all the hemorrhages ceafed, and the pete- 158 
On the Respective 
chise had almoft difappeared. On the 15th, 
they were entirely gone. He continued 
his medicine, however, until the 27th ; 
on which day, his herpes was completely 
Ikinned over. During this time, 'viz. from 
the 3d to the 27th, he took fifteen ounces 
and fix drachms of the cortex. 
The antifeptic virtue of the other gum- 
my refinous vegetables, if we may judge 
of them all by this capital one, the cor- 
texappears alfo to depend on their fer- 
menting in the body; and as thefe fub- 
ftances contain a large proportion of the 
fixed air, they mull part with much of it 
in the courfe of their fermentation : For 
now that we have taken a view of the fe- 
veral kinds of antifeptics, and have feen 
how much the action offalts, and of afirin- 
gents, is limited, we find that the only de- 
pendance muft be on thofe things that 
throw a great quantity of air into the 
blood, if we expeCt to work a complete 
change on the whole mafs. 
If we attend alfo to the things that pre- 
vent putrefaction in living bodies, we fhall 
hill find that the dependence is on the 
quantity of air. Powers of Antiseptics. 
159 
There can be doubt but that it is the 
vegetable part of our food which yields by 
far the greateft fhare of the air, that enters 
the compofition of the animal fluids; and 
vegetable food mod certainly prevents the 
putrefatdive diatbefs. Dr. Pringle afcribes 
it, and with great juftice, to the frequent 
ufe of frefh vegetables and fugar, which 
now make up fo great part of the diet of 
the European nations, that we at this day 
fo feldom hear of the dreadful putrid dif- 
eafes which formerly fwept off fuch multi- 
tudes, every thirty or forty years, and ge- 
nerally went under the name of plagues *. 
The effedts of being deprived the ufe of 
frefh vegetables, are drongly manifefted in 
the fatal fcurvies, fevers, and dyfenteries, 
to which feamen, and people pent up in 
garrifons, are often fubjedt: In fhort, this 
matter is fo well known, and every body is 
fo fenflble of it, that it would be a tref- 
pafs on the reader to inflfl: on every par- 
ticular inftance; I fhall therefore only re- 
quefl:, that he may obferve, in general, 
the kind of diet which is mod wholefome 
* See alfo Hoffman, in the chapter de Venenis in Aerz 
Cantentis, &c. fed, 26, 160 
On the Respective 
in hot climates; that it muft, in order to 
preferve health, confift very much of ve- 
getables, and of thofe kinds which produce 
the greateft quantities of air, in order to 
afford a fuflicient fupply of antifeptic va- 
pour, to make up for the extraordinary 
wafte of air which is carried off from the 
fluids by profufe perfpirations •, and that 
thofe people muff inevitably fall into putrid 
difeafes, who eat much animal food, which 
produceth but little air, who drink much 
fpirituous liquors, that contain no air them- 
felves fcarcely, and prevent the ready ex- 
trication thereof from the aliment, during 
the digeflive procefs, and who incautioufly 
expofe themfelves to a moifl atmofphere, 
which hinders any thing but the aerial 
part of the perfpirable matter to be carried 
off. 
On the other hand, in the cold cli- 
mates, we may more fafely indulge in 
animal food, and in fpirituous and fer- 
mented liquors, becaufe, in thefe, the ex- 
pence of air by perfpiration is fo much 
lefs. 
Taking the matter in this light, we 
may poflibly affign reafons, Powers of Antiseptics. 
161 
x . Why carnivorous animals pcrfpire but 
little ? A fox, though hunted almod to 
death> never fweats. 
2. Why animals, whofe food confids 
entirely of vegetables, perfpire fo much ? 
Horfes and cows, for example; how often 
are thefe creatures feen involved in a cloud 
of their own vapours, and covered over 
"With froth ? 
3. Why animals, whofe natural food is 
vegetables, can be kept alive and in health,' 
in very cold climates, by feeding upon ani- 
mal fubdances ? Cows in Norway and in 
Iceland are fed, in winter, upon fith-bones. 
This general and well-known antifeptic 
quality in vegetable food, is commonly ac- 
counted for by faying, that it produceth 
at efcent chyle ; but ale alefcent or put ref cent 
vegetables are equally powerful, in this 
refpedt, with the acefcent; therefore, the 
antifeptic quality mud depend upon fome- 
what that is general, and common to all 
Vegetables 
* By far the greateft fhare of the vegetables ufed in 
common diet, if we except the fruits and farindcea, are 
alcalefcent or putrefcent; witnefs all the different kinds 
of braffica, the najiurtia, onions, leeks, garlicky horfe-rad- 162 
On the Respective 
Instead of calling chyle produced from 
a vegetable diet acefcenti we fhall fpeak 
with more propriety, as well as approach 
much nearer the truth, by terming it a 
fluid compofed of animal and vegetable 
juices, in the jirji or fweet ftage fermen- 
tation, impregnated and fully charged with 
a fubtile, aCtive, an-d penetrating fpirit, 
which is highly antifeptic. 
This notion of acefcent chyle has fuch 
an influence on the practice of phyfic, that 
it is apt to prefent acids alone to the confi- 
deratioii of the phyfician, in putrid cafes, 
and too often diverts from thofe things 
that are the true oppofers and genuine cor- 
dijh, mujlcrd', raddijhes, fpinnage, endive, purjlain, Ztf- 
; not one of thefe things can be called acefcent, 
and yet they preferve the humours from putrefadfion, or 
correct it when prefent, as effectually as forrel or le- 
mon-juice. We fometimes find in fyfteniatic writers, 
laid down among the general caufes of the putrefaftive 
diathsjis, the too liberal ufe of fuch fort of vegetables > 
but I apprehend there are few, if any, inftances of a 
putrid difeafe arifing from the ufe of any found, fer- 
mentable vegetable. 
Indeed, where people have been obliged to feed on 
fuch vegetables as were unfound, and incapable of the 
alimentary fermentation, there it will readily be granted, 
that the very word: of putrid difeafes have enfued. Powers of Antiseptics. 
fe&brs of putrefa&ion, namely, frefh ve- 
getables, and other fermentable matters, 
which readily yield a large proportion of 
air, fince this, upon comparing all the 
eumftances, will be found the grand anti- 
jeptic *, which not only has the power to 
preferve animal fluids from corruption, but 
can alfo rejiore them, after having under- 
gone fome degree of putrefaction. 
But what proves, almoif to a demon- 
ftration, the antifeptic power of air, is 
the cure of the fea-fcurvy. This difeafe, 
wherein the whole mafs of fluids is dif- 
folved and corrupted, cannot be cured by 
any other means than by throwing in a 
large quantity of new air ; and this muft 
he done in the way of diet; it muft be fur- 
niftied from things that can be taken into 
the body by pounds, not in ounces or 
drachms; and therefore that vegetable is 
found to be the moft powerful antifcorbu- 
tic of which the patient can take the largeft 
* I doubt not but the faying that air is the grand an- 
tifeptic will found oddly at firfl ; but I defire that it may 
always be remembered, that air is the bend of union, 
the vinculum elementorum primarium; and that putrefac- 
tion confifts in a refolution and difunivn of the feveral con- 
stituent particles, On the Respective 
quantity, without occafioning ficknefs, of 
other dilfurbance. 
In the fcurvy, the digejlive organs luck- 
ily preferve their full powers, and therefore 
they can turn the fermentable fubflances, 
taken into the body, to their own proper 
advantage and hence this difeafe fcarce 
ever fails of being cured, provided the re- 
quilite materials be fupplied. 
But in acute difeafes, arifing from pu- 
trefaction, the cafe is far otherwife; every 
thing, here, is thrown into fuch confu- 
lion, that none of the animal procdfes can 
be carried on with regularity ; and, on this 
account, the molt powerful antifeptics, as 
well as every thing elfe, too often lofe 
their power. 
As the cure of the fcurvy, then, feems 
to depend fo very much on the fermenta- 
tive quality in the remedies made ufe of, 
it is not impoffible but other things, as 
well as perfettly frefh vegetables, may be 
found to anfwer this falutary purpofe. 
I imagine that I have found out fuch 
a fubftance; I have had no opportunity* 
indeed, of putting it to the trial * but as 
I am firmly perfuaded that it will be found 
of great fervice, not only in the fcurvy, Powers of Antiseptics. 
165 
but in other putrid difeafes, at fea, where 
frefh vegetables are not to be had, I can- 
not refrain from throwing out a propofal 
for trying new methods of preventing, and 
poffibly curing, thofe deftruCtive difeafes 
that take their rife from putrefaction, in 
fituations where the unhappy patients are 
deftitute of the moft proper means of help; 
but as this requires a particular confidera- 
tion, it fhall be made the fubjeCt of ano- 
ther EJfay. 
However, I will, in the mean time, 
recommend the trial of an experiment in 
that very deflruCtive difeafe, ikiz putrid yel- 
low fever of the Weft Indies. And if thefe 
papers fhall happen to fall into the hands 
of any practitioner in thofe climates, I re- 
queft that it may be tried. 
It is, to give the patients repeated dofes 
of the alcaline falts, in frefh lime-juice, or 
the like, and let it always be fwallowed 
during the aCt of effervefcence; and let 
the patient’s drink be fomewhat of the 
highly fermentable kind; I would even 
propofe the juice of the green fugar-cane, 
diluted, and acidulated with fome of the 
jrecent four juices *. 
# A furgeon, who was fome time at Goree, on the 166 
On the Respective 
Possibly, by throwing in iuch a quan- 
tity of air as would be furnifhed from this 
kind of materials, the putrefactive acrimo- 
ny, which at find feems to be lodged in the 
biliary fyftem, might be corrected and fa- 
turated. 
The principle upon which the faline 
mixtures, when given during the ebulli- 
tion, perform their aCtion of fweetening 
and deftroying the putrefactive acrimony, 
the reader can be no dranger to, or if he 
does not recolleCt it, he has only to turn 
back to the 23d, 24th, and 25th experi- 
ments of this prefent efiay. 
I find that Dr. Lind often prevents the 
fit of an ague, by giving thefe mixtures in 
the manner above-mentioned *. And Ri- 
1verius ufed to check vomitings therewith 
in an inftant; from what the difcontinu- 
coaft of Africa, tells me, that the natives give in thefe 
fevers, with very good fnccefs, a drink prepared by ma- 
cerating in water a fruit of the plumb kind, that grows 
there in great plenty. 
* Which very much ftrengthens the hypothefis which 
I have laid down, in order to account for the operation 
of the cortex in the like cafes; both the one and the 
other appearing to faturate, and fweeten the putrefac- 
tive colluvies, which is lodged in the Jlomach and flexure 
of the duodenum. Powers of Antiseptics. 
167 
ance of this pra&ice hath arifen, I cannot 
undertake to fay, unlefs that fome paflages 
in Boerhaave are fo conftrued as to difcou- 
rage it *; but I am informed, that it was 
in great repute at Edinburgh about thirty 
years ago, and I am perfuaded that the ex- 
hibition of thefe effervefcent mixtures is 
not only perfectly fafe, but, in many cafes, 
will be attended with great and immediate 
advantages. 
* Particularly one in tom. i. p. 528. Though I do 
not find Boerhaave any where abfolutely and exprefsly 
forbid this pra&ice, yet I find that he ufed to do fo in 
his le&ures, if a manufcript that I have feen, of his Col- 
legium Publicum de Aere, be accurately taken. essay iv? 
O N T H E 
S C U R V Y$ 
WITH 4 
Proposal for trying New Methods 
t o 
Prevent or Cure the fame, at Sea. Si quid novijii rettius ijiis 
Candidus impertu Horatius, ESSAY IV. 
ON THE 
SCURVY i with a Proposal for 
trying New Methods to prevent 
or cure the fame, at Sea. 
FO R fome time, even before I engaged 
in the courfe of experiments which 
have been fet forth in the three preceding 
effays, I was firmly of opinion, that the 
cure of the fea fcurvy depended chiefly, if 
not altogether, on the fermentative quality * 
* Although the ingenious Dr. Lind afcribes fome- 
vyhat to the fermentative quality, yet his theory refts 
chiefly on the faponaceous, attenuating, and refolding vir- 
tue, which, according to him, “ is the chief, and moft 
<c eflentially requifite quality, in the antifcorbutic mix- 
“ ture.” P. 304 of his Treatife. 
But when we confider, that the difeafe confifts in a 
refolution of the blood’s fibres, we rauft plainly fee that 
it never can be cured on the above-mentioned principle. 
The theory, which makes the cure to depend on a 172 
On the SCURVY. 
of the frejh vegetables; which are found* 
by experience, to be the only things that* 
with certainty, conquer this deftrudtive 
difeafe. And in confequence of this per- 
fuafion, it occurred to me, that as thefe are 
vegetable fubflances, which, though not 
perfectly recent, are yet capable of fer- 
mentation, fuch in particular as common 
malt; that this, if taken in the way of 
medicine, would, in all probability, pro- 
duce effects fimilar to thofe produced by 
green vegetables, and confequently cure 
the fcurvy; and as malt can be preferved 
found, for a cojifiderable length of time, 
it might be carried to fea, and there kept, 
in order to make wort occalionally as it 
might be wanted; and thus prove a re- 
medy, always in readinefs, againfl that fa- 
tal difeafe. 
Such was the fcheme that I framed to 
myfelf and the more I thought of it, the 
more I became convinced of the likelihood 
of its fucceeding. 
change produced in the difeafed fluids, in confequence 
of the fermentation of the frefh vegetables in the fto- 
mach and bowels, was firft taught (as 1 am informed) 
by Dr. Cullen, the celebrated profeflor of chemiflry at 
Edinburgh, but was fuggefted to me by Dr. Hutchefon. On the SCURVY. 
173 
I soon mentioned this affair to a fet of 
medical friends, who having formed them- 
felves into a little fociety, meet once a 
fortnight for their mutual improvement; 
and they thought the reafons on which my 
expectations were founded fo plaufible as to 
deferve the trouble of an experiment: So 
that all that was now wanting was an op- 
portunity of putting it to the fair trial. 
But as the fcurvy * is a difeafe very 
rarely to be met in this city (Dublin), and 
as I had not any acquaintance at the places 
where cafes of this fort occur moft fre- 
quently, I drew up my reafons for think- 
ing that the wort would prove a remedy, 
in the form of a letter, and addreffed it to 
my very worthy friend Mr. George Cleg- 
horn, leCturer of anatomy in the univerfity 
of Dublin, with a defire that he would 
fend it to fome of the leading medical peo- 
ple in London, in order to engage them in 
an application to the gentlemen who have 
the care of the naval hofpitals, that trial 
* The genuine putrid fcurvy, fo fatal to Teamen, and 
to people {hut up in garrifons without fupplies of frefh 
vegetables, is the difeafe every where meant throughout 
this Effay, 174 
On the SCURVY. 
might be made of its effects at thofe 
places. 
Among the gentlemen to whom 
Cleghorn tranfmitted copies of the letter,- 
were Dr Hunter, and Henry T’cm, Efq.; 
one of the cQmmiJJioners for taking care of 
fick and woundedfeamen, whofe zeal in the 
profecution of this affair, and in endea- 
vouring to get the propofal carried into 
execution, demands a publick acknowl- 
edgement i fince it was through their ap- 
plication, that the lords of the admiralty did, 
in the month of May, 1762, give orders 
to have the wort tried in the naval hofpi- 
tals at Portfmouth and Plymouth. 
But as it was abfolutely neceffary, in 
order to determine the genuine effects of 
the remedy propofed, that the patients 
fhould, during the time of trial, be en- 
tirely debarred from any fort of recent ve- 
getable, this reflridtion was deemed fo fe- 
vere, and looked fo like retarding men’s 
cures for the fake of experiment, that it 
occafioned a general murmur and difgufl, 
and, of courfe, put a flop to the further' 
exhibition of the wort at the hofpitals. 
Orders were then iffued to have it given on 
ihip-board, while at fea, where no temp- On the SCURVY. 
tations of frefh vegetables would offer to 
make the men uneafy, and where it was 
expected that the patients would chearfully 
fubmit. 
But hitherto *, no return has ever 
been made to the offices, either of the good 
or bad effedts of the wort whether this 
hath arifen from difobedience, or inatten- 
tion, is not eafy to determine; poffibly, 
each may have had its fharej for, of all 
men, thofe who ufe the fea, are the moll 
averfe from innovation and experiment. 
But neverthelefs, as I am now, in con- 
fequence of thofe experiments which have 
been already made known to the reader, 
more than ever convinced that the cure of 
putrid difeafes in general, and that of the 
fcurvy in particular, depends greatly on 
* In a letter dated 17th Feb. 1763, which I was fa- 
voured with from Conunijfioner Tom, I was told, that at 
that time none of the navy-furgeons had reported any 
thing concerning the Wort; but Mr. Tom engaged to 
acquaint me of the particulars, as foon as a return Ihould 
be made to the office. 
But as I have never had the pleafure of hearing from 
that gentleman fince (it is now 4 March, 1764), I take 
it for granted that nothing has been done in confe- 
quence of the admiralty’s order, nor any report ever 
made. On the SCURVY. 
the quantity of new air thrown into thd 
blood from eafily fermentable fubftancesi 
I fhould deem myfelf wanting of common 
humanity if I did not communicate this 
to the public, and make it my requeft, 
that fuch people as are concerned in long 
voyages may embrace fome opportunity of 
giving the wort a fair trial; for until it is 
difproved by adlual experiment, I fhall 
ftill continue to think, that this liquor 
bids as fair to cure the jcurvy as the juice 
of any recent vegetable. The experiment 
can occafion no poffible danger, will be at- 
tended with very little expence or pains, 
and, if it fucceeds* will make ample 
amends, in producing a difcovery of infi- 
nite advantage to the feafaring part of 
mankind. 
If it be true what was published in De- 
cember, 1762* taken, as is fuppofed, from 
returns made to the houfe of commons, 
that of one hundred and eighty-jive thoufand 
men, raifed for the fea fervice, during the 
late war, above an hundred and thirty thou- 
fand perifhed by difeafes, and that two 
thirds of this number may be fafely charged 
to the account of difeafes which take their 
rife from putrefa&ion s furely, every mo- On the SCURVY. 
live of policy and humanity fhould excite 
men to endeavour at finding out fome- 
what to check this fatal and deftruCtive di- 
et hejis ; for if feamen could be preferved 
from it, few other kinds of difeafes would 
endanger them. 
For a fea-life, fimply confidered, is fo 
far from being productive of difeafes, that 
it is found to be a remedy againft fome of 
the moil dangerous kinds *; and though 
habitual intemperance, and incautioufly 
expofing themfelves to heat and cold, may, 
and frequently do, cut fhort the lives of 
feamen, yet the great mortality to which the 
crews of the king’s fhips are too often fub- 
jeCt, arifeth from infectious difeafes, ow- 
ing to fuch numbers being crowded toge- 
ther, and living in circumftances lefs 
cleanly than is ufual in the merchants fer- 
vice, where the men breathe a purer air, 
and are in general cleaner, and better 
cloathed, though by no means better, nor 
perhaps fo well, fed, as in the royal navy. 
Whoever has read Dr. Lind's excellent 
treatife on the feurvy, mull be convinced 
* See GilchriJPs ingenious difcourfe on the ufe of Sea- 
Voyages in Medicine. 178 
On the SCURVY. 
that the principal and main predifpofmg caufe 
is too great a degree of moijiure in the at- 
?nofpbere> whether hot or cold, but more 
efpecially the latter; and that the ufe of 
fait diet, bad water, or foul air* can only 
be reckoned as fecondary caufes, which 
will not of themfelves produce the difeafe. 
The manner in which excejjive moijiure* 
brings on the putrefactive diathejis, we have 
already attempted to explain 3 and have 
endeavoured to point out the mod: effectual 
methods of preferving the body from its ill 
effects. 
It has been alledged, that this depends 
very much on keeping the furface of the 
body always warm and dry, by wearing 
enough of clean apparel to abforb the 
aqueous part of the perfpirable matter 3 and, 
at the fame time, making ufe of fuch diet 
as will fupply a fufficient quantity of new 
air, and which is known, from expe- 
rience, to correct the morbid difpoftion, 
or tendency to putrefaction. 
But here a queftion naturally prefents 
itfelf j where are the bulk of the crew, the 
poor common failors and marines, to get 
fuch kind of diet ? or how are they to be 
always kept clean, dry, and warm, who, On the SCURVY. 
for the moft part, have not a fecond fuit, 
but are obliged frequently to lie down in 
wet cloaths, and go to deep in damp ham- 
mocks ? 
To this it may be anfwered, let the 
men in the navy be cloathed in the fame 
regular, exad, and uniform manner as 
they are in the army; and let them be al- 
lowed, while at fea, a daily portion of fu~ 
gar; and I will venture to promife, that, 
in a time of war, we fhall annually fave 
fome thoufands of very ufeful lives. 
When thinking on this fubjed, I have 
often lamented, that it has never been at- 
tempted to cloath the feamen in this man- 
ner. Such a fcheme, as it would occafion 
confiderable changes in the prefent naval 
fyftem, could not be carried into execution 
without fome difficulty j but if it were 
once eftablifhed, it would certainly be pro- 
dudive of great and folid advantages for 
it would attach the men more firmly to the 
fervice, and prevent a great deal of defer- 
tion, by infufing more powerfully that 
efprit du corps, which binds people fo 
ftrongly together; and it would, without 
all manner of doubt, render the fleet much 
more healthy; for the greateffi fhare of 180 
thofe terrible putrid difeafes, that fweep 
off fuch multitudes of our feamen, take 
their firft rife from a want of neceflary 
cloathing ; a fpecies of diftrefs which 
numbers of people, as things are now or- 
dered on board the king’s fhips, muft often 
labour under. 
The great importance of neceflary 
cloathing may be plainly feen, by obferv- 
ing what happens to the commiftion, war- 
rant, and petty officers, on board the fleet; 
together with fuch of the common feamen 
as are careful and provident, and pride 
themfelves upon being always neat and 
well cloathed. Thefe people are fcarce ever 
feized with acute putrid difeafes, except- 
ing by mere infection, and they are very 
feldom known to become fcorbutic, to any 
violent degree, unlefs the general caufe 
(exceffive moifture) be of a remarkably 
long continuance. 
Now, the diet of all this fet of men 
(the commiftion, and feme of the warrant 
and petty oflicers excepted *) is precifely 
On the SCURVY. 
•* If thefe gentlemen fare better than the reft of the 
crew, it muft be all at their own expence ; for the go- 
vernment provides nothing better for the officers than 
it does for the mcaneft perfon in the fliip. On the SCURVY. 
181 
the fame with the reft of the crew, being 
nothing better than the common fhip’s 
provifions ; and many of the petty officers 
fleep in a part of the fhip, where the air 
muft be even more confined than it is 
where the common men fleep. 
The only circumftances wherein the 
people of whom we have been fpeaking 
ufually differ from the common run of the 
crew, are, that they are well clad, and, 
for the moft part, never want a little ftore 
of fugar. 
It would lead me from my purpofe to 
purfue this matter any further; but the im- 
portance of it is fo obvious, that I moft 
heartily with that fome perl'on, whofe rank 
in life would infure him the public atten- 
tion, would take the hint, and offer a plan 
for the regular cloathing of the feamen in 
the royal navy; the time being now come 
whenfuch a thing might eafily be attempt- 
ed : the naval eftablifhment being brought 
fo low, and the feveral commanders fixed 
to their fhips, for at leaft fome years, will 
give leifure and opportunity for trying if 
fuch a fcheme can be carried into execu- 
tion.  On the SCURVY. 
But altho’ the cloathing fcheme fhould 
never take place, yet the other part of the 
propofal may be eafily adopted; and I 
fincerely wifh that fugar or melajjes may 
hereafter be allowed, as a part of fea-pro- 
*viftons, 
The expence, even taken at the higheft, 
is too trifling, when put in competition 
with preferving fo valuable a part of the 
community as our feamen ; but I am con- 
vinced, that the government would rather 
be gainers by affording the feamen this 
allowance; for the favings at the hofpi- 
tals, which would not then be crowded in 
the manner they have often been, would 
more than pay for all the fugar expended 
at fea. 
The reader muff have already perceived 
the principle upon which it is propofed to 
cure the [curvy by the ufe of frejb tyort; 
but as I do not imagine that any perfon will 
take the trouble of making the experiment, 
tmlefs he is aimoff as fully perfuaded as 
myfelf, I am under the neceffity of enter- 
ing into a farther explanation of the rea-? 
fons which lead me to expedt that this li- 
quor will produce fuch falutary effedts. On the SCURVY. 
183 
Notwithstanding the many impu- 
dent affections every day published in the 
common news-papers, which, among other 
much-boaffed remedies, promife not a few 
as peculiarly fpecific againft the /curvy *, 
yet it may be laid down as a pofition, not 
eafily to be controverted, that the genuine, 
putrid feurvy has never been known to 
yield to any other medicines than to fuch 
as are compofed of frejh vegetables jp; and 
* If any of thefe noftrunts be fpirttuous tinctures, the 
material from whence they are extracted, if it ever had 
any antifcorbutic virtue, mull: be deprived of it by this 
manner of treatment; and the tindture itfelf muft be fo 
far hurtful, as every kind of ardent fpirit is found to be 
extremely pernicious in this difeafe. 
If they be mineral acids, they are fufficiently known 
from experience to be ufelefs, either as remedies or pro- 
phylactics. 
But if they contain mercury, they muft be as fo much 
poifon ; for mercury breaks down the blood, and den 
ftroys its texture, in like manner with the fcorbutic 
acrimony. 
f The only places where I meet with any thing like 
a contradidlion to the above afiertion, are in BiJJet’s Ac- 
count of the Scurvy, and in the Hiftory of the Voyages 
made by the RuJ/ians in order to difcover the American 
coafts oppofite to Kamtscbatka. 
The firft-mentioned author thinks that many people 
cured at Cumberland Harbour, in the ifland of 184 
On the SCURVY. 
provided they be frejh, and of fuch a na- 
ture as will allow them to be taken freely, 
it is almoft no matter what they are. The 
acid and the alcalefcent, the mild and the 
acrid, the fweet and the bitter, all of them 
cure the /curvy; though their fenfible qua- 
lities be fo oppofite, and their manner of 
affe&ing the body, in ordinary cafes, be fo 
different. 
This virtue, then, muft be owing to 
fome property which they all poffefs in 
common. 
The experiments of the three preceding 
elfays will, as I apprehend, be allowed 
conclufive, in fhewing that a property, 
common to allfrejh vegetables, is, that when 
mixed with any animal fubflance, and 
placed in the proper degree of heat, they 
Cuba, merely by feeding on rice, and before they were 
fupplied with apy recent vegetables. (See p. 83 of his 
7'reatife. 
And in the laft-mentioned book the cure is entirely 
afcribed to eating the flelh of the fea-cow. But the au- 
thors do not take notice, that the fame fpring-feafon, 
and warm weather, that induced thefe animals to feek 
the land, mult alfo have thrown up a variety of vegeta- 
ble productions, which the fcorbutic patients would 
molt greedily devour, without waiting for the doCtor’s 
directions.- On the SCURVY. 
185 
prefently run into fermentation, and, in the 
courfe of that fermentation, throw off an 
elaftic vapour, or fpirit, of furprifing ac- 
tivity, endued with a power of rejioring 
fweetnefs to putrid animal fluids. 
This hath bce.i fo clearly and fo abun- 
dantly proved already, that there cannot 
be the leaf! neceflity for repeating what 
hath been faid of it in the three foregoing 
effays ; I fhall therefore only mention fome 
circumftances with regard to the cure of 
the fcurvy, which will afford almoft a de- 
monflration that it depends on the change 
brought about in the difeafed fluids, by 
the action of the fubtile, adtive, and pene- 
trating fpirit, which is generated during 
the fermentation of the frefh vegetables, 
carried on in the firft paffages. 
First, the recovery of people in the 
very lafi ft ages of the f curvy, is brought 
about in a furprifingly fhort fpace of time, 
provided the patients are but fully fupplied 
with frejh vegetables. This is fufficiently 
confirmed by every account of the feurvy 
that we meet with ; and ’John Woodall, ail 
pld Englifh furgeon *, who hath left us a 
* Although Woodall was a man of great eminence in 186 
On the SCURVY. 
very accurate defcription of the difeafe, 
paints this falutary change in a very ftrik- 
ing manner, by faying, ££ That to any 
££ man of judgment it may feeme a won- 
££ der, how a poore miferable man, com- 
££ ing on lande from a long voyage, even 
££ at the point of death, namely, fwolne 
<£ fometimes to an exceeding greatneffe, 
££ not able to lift a legge over a flraw, nor 
££ fcarce to breathe, by reafon of ftrong 
£* obftru£tion, yet, in a few dayes, fhall 
his day, and of no inconfiderable merit as a writer, yet 
his book appears to be very little known. The only 
places where I fee it mentioned, are in Wifeman s pre- 
face, and in the preface to Turner s furgery ; but it is 
not to be found in Haller’s catalogue, neither in Heif- 
ter’s Bibliotheca Chirurgica-, nor, which is ftill more to be 
wondered at, in Lind's Bibliotheca Scorbutica j notwith- 
ffanding that Woodall hath left a very excellent difcourfe 
on the fcurvy, his defcription of which appears to have 
been drawn from his own obfervation, and his method 
of cure founded on experience, for he ferved both at fea 
and in the army. For thefe reafons, I am perfuaded 
that the reader will be pleafed to fee an extract from 
this part of his works, which confifts of feveral dif- 
courfes on medical, chemical, pharmaceutical, and chi- 
rurgical fubje&s, printed originally at different times, 
but all colle&ed by himfelf, and re-publifhed in a thin 
folio, i n the year 1639, with a dedication to King Charles, 
under the title of The Chirurgeon s Mate, or military and 
clomefucke Surgery, On the SCURVY. 
187 
s( receive the fulnefs of former healthe, 
“ yea, with little or no medicine at all.” 
Surely this change muft be wrought 
by fomewhat of amazing a&ivity, and does 
not depend on a faponaceous, attenuating, 
or refolding virtue for in the fcitrvy the 
crajis of the blood is broken and defrayed 
te by the fcorbutick putrefaffion” and cer- 
tainly never can be reftored to a found 
Rate, by being further attenuated and re- 
folved neither have we fufficient time, in 
thefe cafes, “ for the putrefactive acri- 
“ mony to be diluted, and obtunded by the 
“ watery and mucilaginous parts, and car- 
t( ried out of the body by the aperient qua- 
tc lity of the vegetable juices ” Nor does 
the mechanical adtion of “ fcourtng and 
“ cleanfng the furred and obf ruffed paf- 
“ fages t^ie machine at all correfpond 
or agree with the appearances that attend 
the progrefs of the cure; which is always 
found to depend on vegetables only fo far 
as they are frejh and capable of yielding a 
large proportion of air\ for although the 
dry farinacea, when mixed with the ani- 
mal juices, ferment very readily, yet both 
See Lind an the Scurvy, p. 304, 3 06. 188 
On the SCURVY. 
reafon and experiment {hew, that they will 
not do it with fo much eafe, nor produce fo 
much air, as the frefh fucculent vegetables; 
therefore, notwithflanding that bread, with- 
out any other vegetable affiftance, will 
ferve, in ordinary cafes, to raife the com- 
mon and neceflary alimentary fermenta- 
tion, and produce enough of the antifeptic 
vapour to prcferve the juices in a found 
hate; yet if a putrid acrimony hath once 
taken place in the conftitution, the crude 
and dry farinacea are found quite inef- 
ficient to conquer it 5 and there is then an 
abfolute neceflity for throwing in a large 
quantity of frefh vegetable juice, in order 
not only to obtund and {heath the putre- 
factive acrimony by its mucilaginous qua- 
lity, but alfo, by its fermenting in the 
bowels, to generate a efficiency of the 
fubtile fpirit, which feems to be the only 
thing capable of pervading, in fo ffiort a 
time, the moft intimate recedes of the 
whole vafcular fyflem, and of totally 
changing the corrupted nature of the 
tire mafs of fluids. 
Secondly, the liquors which have 
completed their firfl: ftage of fermentation, 
and thereby loft much of their fixed airy On the SCURVY. 
189 
though they are found ufeful as preferva- 
tives, will none of them cure the difeafe : 
Gyder, which appears to have a greater 
degree of antifcorbutic virtue than any of 
the common fermented liquors, is gene- 
rally flopped fooner in its career of fermen- 
tation, and contains the more fixed air on 
that account*. 
Thirdly, acids -f*, both mineral and 
vegetable, and ardent fpirits J, which 
* See the note in page 147. 
Cyder was once carried to fea, as part of the fea-pro- 
vifions, on the recommendation of Dr. Huxham ; who 
finding, “ that the juice of apples did moft certainly 
“ cure the fcurvy, imagined, that the fame juice, when 
46 become a vinous liquor, could not but be very falu- 
“ tary.” 
The cyder, howevrer, was found to avail but very lit- 
tle, as may be learned from Mr. Ives's letter, publifhed 
by Dr. Lind. P. 194 of his Treatife. 
It was not at that time fufpe&ed, that the antifcor- 
butic virtue of the apple-juice depended on a principle 
that muft, in great meafure, be diflipated, during the 
aftion of that fermentation which makes it a vinous 
liquor. 
t 44 Experience has abundantly fhewn, that they 
44 (Sp. Sails, Elix. Vitrioli, and Vinegar) have not been 
44 fufficient to prevent this difeafe, much lefs to cure it.” 
Lind, p. 187. 
+ This is ftrongly proved by the remarks of governor 
Ellis, in his account of the Voyage to Hudfsns Bay.  On the SCURVY. 
contain little fixed, air in themfelves, and 
check the alimentary fermentation, are 
found to be, the hr ft, ufelefs and infigni- 
ficant, and the fecond extremely hurtful, 
in the difeafe. 
Upon the whole, then, it may fafely be 
repeated, that the cure of the fcurvy de- 
pends on the fermentative quality in the re- 
medies made ufe of. 
And this being the cafe, we have only 
to find out a fubftance which may be pre- 
ferved for fome confiderable length of time, 
and yet {hall contain materials for railing 
a fermentation in the bowels like that 
raifed by frefii vegetables; and then, in all 
human probability, wTe fhall have a remedy 
for the fcurvy always in readinefs. 
Such a vegetable fubftance, it is pre- 
fumed, is common 7nalt. 
Grain, after it is malted, differs widely 
from grain in the crude fiate ; by the ger- 
mination, drying, and flight torrefa<5tion, 
its natural vifcidity is deftroyed, it acquires 
an agreeable faccharine tafte, and the fari- 
naceous part is fo attenuated as to be 
dered foluble in water. 
Fresh wort, or infufion of malt, is a li- 
quor fimilar to the recent juices of the fweet vegetables; fermenting readily like 
them, and being precifely of the fame 
mild, faponaceous, and aperient nature. 
What then fliould hinder it from pro- 
ducing the very fame effects ? and, as it 
may be taken in as large a quantity, with 
as much fafety, and with as little difguft, 
there can be no reafonable objection to its 
being given. All that remains, then, is 
to put it to the fair trial; and this I cer- 
tainly fliould have done, long ago, if an 
opportunity had ever prefented itfelf. 
But the fame objections that were made 
at the naval hofpitals, muft always be 
made, as often as the experiment is at- 
tempted on fhore; therefore, whenever it 
fhall be fairly tried, it muft be at fea. 
Let me then again requeft, that fuch 
of my readers as may have opportunities, 
will try the effeCts of this liquor * : and 
this is a matter of fuch importance, as to 
render it well worth the beflowdng of fome 
expence and pains, for if the wort fhould 
On the SCURVY. 
* The Eajl-lndia Company would do well to order 
fome malt to be carried out in their {hips, and give po- 
fitive directions to have trial made of its efFeCts, as there 
never fails to be abundance of opportunities during the 
courfe of thefe voyages. 192 
On the SCURVY. 
be found to anfwer, it will undoubtedly 
be the means of faving the life of many a 
brave fellow. 
For malt, as I am allured by the brew- 
ers, with proper care, may be preferved 
found and good for years ; fo that if it 
were previoufly well dried, packed up in 
fmall calks, and flowed in the bread- 
room, or fome very dry part of the fhip, 
it might be carried to fea, and kept for 
any length of time that would be required, 
even in the longefl voyages; and as there 
need be no very large quantity carried, it 
would not incommode the fhip by its bulk; 
fince I do not mean, that it fhould be 
given as a part of the common diet, in the 
way of prefervative, but only to fuch as 
are actually lick; when the malt is to be 
ground, and made occafionally into wort, 
as it may happen to be wanted. 
The method in which I would propofe 
the wort fhould be given, is, to boil it up 
into a panado, with the fea-bifcuit, or fome 
of the dried fruits that are ufually carried 
to fea; then let the fcorbutic patients 
make at leafl two meals a-day on this pa- 
latable mefs, and let them drink a quart, 
or more, if it fhall be found to agree, (al- On the SCURVY. 
Ways beginning, however, with a fmaller 
dote, and gradually increafing it) of the 
frejh infujion, in the courfe of the twenty- 
four hours. 
Its moft likely effedt will be to open 
the belly, a moft agreeable circumftance to 
the poor fcorbutics (in whom obftinate 
coftivenefs is a very common lymptom), 
and exadtly ftmilar to the modus operandi of 
the moft powerful green antifcorbutics. 
But like them too, if taken too liber- 
ally, it may occafion griping, and immo- 
derate purging; when this happens, the 
dofe muft be leftened, and fome drops of 
the acid elixir of vitriol may be given with 
it, in order to check the too great ten- 
dency to fermentation, and make it fit eafy 
on the ftomach. 
And it is not only in the fcurvy, but 
likewife in acute putrid difeafes, that I ex- 
pert the wort will be found of lingular fer- 
vice. In all fuch where the putrefactive 
acrimony feems to be unaccompanied with 
any peculiar pefiilential taint, it promifeth 
to produce very good effedts, from the 
principles already laid down ; for as moft 
of thefe fimple putrid difeafes arife from 
an accumulation of fharp and corrupted 194 
On the SCURVY. 
matter, in the firft paffages, fuch medi- 
cines as will dilute, obtund, and above all 
ferment, and, in that adlion, produce a fuf- 
ficiency of the antifeptic vapour to faturate 
and fweeten the putrefadtive colluvies, bid 
the faireft to give prefent relief. 
In thefe cafes, the wort may make a 
principal part of the lick perfon’s diet; a 
thin panado for meat, and the plain infu- 
fion, acidulated with lemon or orange- 
juice, if to be had, if not, with fpirit of 
vitriol, for the common drink. 
And this will bring things as near as 
the circumflances and fituation will allow, 
to the very fuccefsful pradtice of the cele- 
brated De Haen, at Vienna. In acute, 
continual, putrid fevers, his method is 
truly Boerhaavian and fimple, confiding 
only in fupplying the patients liberally with 
oaten or barley gruel, fweetened with ho- 
ney, and made of different degrees of thick- 
nefs, according as he intends it for meat or 
for drink though, in fome cafes, they 
are indulged with flefh broth, made very 
light and thin. If the belly is not made 
foluble by the gruel alone, he occafionally 
mixeth a little cream of tartar, or nitre : 
His medicines are all of the frefh fermen- On the SCURVY. 
195 
table kind j flowers, leaves, fucculent-roots, 
and ripe fruits, made into decoCtions, or 
infufions, according to the nature of the 
different materials : And his only cordials 
are decodtions of bread, made palatable by 
the addition of the more pleafant kinds of 
fruit, when in feafon, or, at other times, 
by the fame, preferved, and made into jel- 
lies, fyrups, or what is ufually called jam » 
with now and then fome fmall dofes of the 
milder antimonials, or fome of the neutral 
falts: Nor does he ever give his patients 
any of thofe trifling and infignificant mix- 
tures which fill up the German difpenfa- 
tories. 
By thefe plain, fimple, and pleafant 
remedies, he finds the extraordinary fick- 
nefs and naufea, which attend all thefe pu- 
trid fevers at the beginning, is prefently al- 
layed ; infomuch, that he fcarce ever thinks 
of giving an emetic. The tormenting thirft 
is fo effectually relieved, by thefe diluent, 
mild, and faponaceous drinks, that the pa- 
tients very foon forget to complain of it; 
and by their power, likewife, the putrid 
acrimony which occafioned the difeafe, is 
early obtunded and corrected, the difturb- 
ed fecretions are prefently reftored to or- 196 
der, and the whole mafs of humours pre- 
ferved from corruption and dilfolution: 
Hence, patients with petechial and mili- 
ary eruptions, proceeding from a diffolved 
flate of the fluids, are rarely to be feen in 
the hofpital that De Haen has the care of; 
neither are his patients afflicted with vio- 
lent vomiting or purging, the acrimonious 
matter being fo early corrected, that even 
the appetite frequently returns, during the 
very courfe of the fever *. 
DE HAEN, agreeable to the common 
theory, makes the virtue of all thefe things 
to depend on their producing acefce?it chyle 
but how liable this way of accounting for it 
is to objections, the reader hath already been 
informed : It is on account of their fer- 
mentative quality, and on their producing 
much of the antifeptic vapour, that all thefe 
things perform fuch wonders; and if they 
actually do perform them, there is all the 
reafon imaginable to expeCt that the wort 
will not come far fhort : I do therefore 
again molt earnestly recommend a trial of 
it, in the acute, as well as in the chronic, 
putrid difeafes. 
On the SCURVY. 
. * De Hacn} Ratio Medendi, in capite i° & 2°. On the SCURVY. 
197 
It is known, from certain experience, 
that all thefe mild, fermentable fubftances, 
will cure a chronic putrid difeafe, as lurely 
as opium will procure reft; and, were it not 
for two reafons, they perhaps would alfo 
cure all acute putrid difeafes. 
First, in many of the acute difeafes, 
the acrimony is not /imply putrid, but is of- 
ten attended with a certain peftilential 
principle, which being fuperadded to the 
general putrefactive caufe, induceth a pe- 
culiar morbid difpoftion, not conquerable 
by any medicine yet known, but which 
muft depend merely on the vital powers, 
to concoCt and expel it, either in the form 
of fome eruption, or by fome critical eva- 
cuation. 
And, fecondly,. even fuppofng the acri- 
mony to be fimple and unaccompanied, yet 
the feveral functions of the body are fo 
early difturbed, and fo totally difordered, 
by the febrile commotion, that although 
the patient be plentifully fupplied with 
fuch things as would infallibly correCt the 
putrefaction, in circumftances where the 
digeftive organs could turn the remedies to 
their own proper advantage, yet here they 
gre found to produce no fenfible change; 198 
On the SCURVY. 
other, becaufe the animal juices have loll 
their power of railing the natural alimen- 
tary fermentation, or the la&eals, con- 
flricfted by the frebile fpafm, obhinately 
fhut their orifices, and refufe admittance 
even to the mildell and mofl falutary ap- 
plications. And hence it is, that acute 
difeafes (excepting fuch as are purely in~ 
fiammatory) are, for the moft part, found 
inflexibly to perfifl: in running through 
their hated periods, in fpite of direct op- 
polite methods of treatment *. 
Although I have all along infilled on 
the wort, as thinking it comes the neareft 
to the frejh juices, in every refpedt, yet, 
where malt is not at hand, I would recom- 
mend that melajfes, honey, or fugar may 
* This conftancy of nature, in the progrefs of fome 
difeafes, appears very remarkable in the tertian fevers of 
Minorca. See Cleghorn’s excellent difcourfe on the dif- 
eafes of that ifland, p. 140. 
■f Dr. who has very fanguine expectations from 
the wort, thinks that fugar bids fair to cure the fcurvy, 
as well as the wort: And it certainly does fo ; for the 
fame reafons that lead us to expert that the one will 
prove a remedy, hold good, in almoft every circum- 
ftance, with regard to the other. 
New fpruce beer is known to be a mo ft powerful an- On the SCURVY. 
199 
be tried, diffolved in a due proportion of 
water (about four to one) and given in 
manner as may be found mofl agreeable 
and convenient to the patients. 
The method in which it is propofed to 
prepare the wort, is, to take one meafure 
(fuppofe a quart) of the ground ?7ialti and 
pour on it three meafures of boiling water; 
flir them well, and let the mixture fland, 
clofe covered up, for three or four hours; 
after which, ftrain off the liquor. 
It mull be brewed, in hot weather 
efpecially, frefh every day; for if it be al- 
lowed to grow vapid, or fourifh, it will not 
only be unpleafant, but ufelefs, as it would 
not then run eaftly into fermentation; but 
tifcorbutic; but this virtue feems to depend chiefly on 
the melaffes that is mixed therewith in order to make 
it ferment; for I apprehend that a decodlion of dried 
fir-tops, alone, would no more cure the [curvy, than 
the decodlion of any other dried vegetable, great va- 
riety of which have been tried, but always without 
fuccefs. 
Honey, on the fame principle, muff be a good anti- 
fcorbutic, and, as fuch, may be recommended to offi- 
cers, and others who can carry it conveniently, to eat 
fome daily, which would, in all probability, keep off 
the extreme coftivenefs to which people at fea are fo 
yery liable. 200 
On the SCURVY. 
when perfectly frefh, there cannot well be 
a more palatable kind of drink, and I dare 
fay, that, in general, it will fit light and 
eafy on the ftomach. 
If what hath been urged fhall be found 
of fufficient weight to engage any gentle-* 
man in a trial of the wort, all that I have 
further to requeft, is, that he will, pre- 
vious to its adminiftration, carefully and 
particularly note down the cafes in which 
it is given j defcribing with accuracy the 
feveral fymptoms, and relating fairly, and 
with candour, the progrefs and effects, 
from time to time; and let thefe obferva- 
tions be communicated, either to the pub- 
lic at once, or to the author at Dublin, APPENDIX. 
A *1 
Extract from that Part of Wood- 
all’s Work which treats of the 
Scurvy. 
HE prefaceth his difcourfe on the 
fcurvy with lamenting, “ That 
“ none of his countrymen had, out of 
“ their experience, taken in hand fincerely 
“ to fet down to pofteritie the true caufes, 
“ flgnes, and cure thereof $ neither left 
{e any caveats, inflrudtions, or experiences, 
“ for the prevention or cure of the fame.” 
He therefore declares his intention <c of 
“ informing the chirurgeon how he fliould 
“ demean himfelf, to comfort his patient 
“ at fea, in that mod: dangerous difeafe 
which, he tells his reader, “ is a difeafe of 
<s the fpleene, whereby it is fometimes 
44 wholly flopped, and fometimes only dif- 
f* tempered.” APPENDIX. 
Having bellowed a paragraph or two 
on the different names of the difeafe, he 
goes on to treat of the caufes, figns, and 
method of cure, expreffing himfelf in the 
following terms. 
“ The caufes are fo infinite and un- 
“ fearchable, as they far exceede my ca- 
“ pacity to find them out: Some men 
*€ conceive this difeafe happeneth unto 
“ feamen only through their being long at 
“ fea without touching at land, as at their 
“ coming on land they prefently grow 
“ flrong again, and .are, by the very frefli 
te aire, and frefh food, cured, without 
“ much other helpe. The chief caufe 
“ thereof is the continuance of fait diet, 
ci which is not to be avoyded at fea, want 
“ of fufficient nourifhment, and of fweete 
<e water $ and alfo for want of aqua vita, 
“ wine, beer, or other good water, to 
<£ comfort and warme their flomachs 
“ all. 
£< Another caufe of this difeafe, to 
tc the ordinarie forte of poore men, is want 
<e of frefh appa?~el to fhift them with 
“ which, indeed, among poore failors, 
“ efpecially a forte of them that are care- 
<e lefs and lazie of difpofition, is too fre- APPENDIX. 
eC quent; partly alfo by not keeping their 
“ apparell fweet and dry, and the not 
** cleanling and keeping their cabins fweet; 
“ this alfo ingendreth and increafeth the 
*e infection. Some charge bilket as a caufe 
*e of the fcurvy, but I am not of their opi- 
<c nion; fome fay inordinate watchings are 
“ the caufe thereof; fome fay, extreme 
“ labour, wanting due nouriffiment; fome 
<c alfo affirm cares and grief to be the 
cc caufe thereof; others affirm, the very 
ct heat of the aire, refolving the fpirits. 
ce But what fhall I amplify farther ? for it 
“ is alfo true, that they which have all the 
<e helpes that can be had for money, and 
C( take as much care as men can devife, 
ec are, even by the evil difpofition of the 
<c aire, and the courfe of nature, ftrooke 
“ with a fcurvie, yea, and die thereof, at 
“ fea and land both. 
“ The lignes of the fcurvie are many; 
(t as, namely, a general lazinefs and evil 
*e difpofition of all the faculties and parts 
i{ of the bodie, laving the ftomach and 
tc appetite, which oftentimes is greater 
than ordinarie, with them, for a long 
ff time, 204 
APPENDIX. 
“ A discolouring of the fkin, as if 
<e it were fouler than ordinarie, with fpots 
cc darker coloured than the reft, and fome- 
“ times alfo darkifh blew fpots. 
“ A fever at fea commonly ends in 
“ the fcurvy; wherefore, beware of too 
“ large bleeding, which oft increafeth the 
ct griefe and maketh it incurable. 
“ Also itching, and aching of the 
“ limbs, are fignes of the difeafe. 
“ Sometimes, alfo, the legges falling 
“ away and drying, and the calves of the 
“ legges growing hard and dry; as alfo 
“ immoderate fwellings of the legges. 
“ Also the legges and thighes difco- 
“ loured into frekells or fpots, of a dirty, 
“ brown, fad colour, much like the co-» 
lour of a gangrenated or mortified 
i( member. 
“ Stinking of the breath, greate ob- 
tc ftrudtions of the liver, or fpleene, or 
“ both; and, in the exercife of their bo- 
dies, their limbs and their fpirit failing 
“ them. 
•£ Shortnesse and difficultie of breath- 
<e ing, efpecially when they move them- 
“ felves, but lying ftill, find little griefe 
f( or paine. APPENDIX. 
205 
(t Their eyes of a leady colour, or like 
€t dark violets. 
“ Great fwellings of the face, legges, 
U and all over the body; palenefs, or a 
iC foul pale colour in the face; fwellings 
“ in the gums, rottenefle of the fame, 
“ with the ilfuing of much flthie blood, 
ft and other finking corruption thence; 
“ loofenefle of the teethe : Alfo fome are 
“ troubled with extreme coftivenefs, that, 
“ for fourteen days together, they go not 
“ to ftoole once; alfo many have ftop- 
(e pings of the urine, or, at the leaf, 
“ making lefs water in two days than the 
** partie drinketh in one. 
“ A coldnesse and ftiffhefe of the 
iC f newey parts chiefly of the legges; fome 
“ alfo have their mufcles, yea, and the 
“ finewes of their thighes, arms, and 
f{ legges, fo wafted away, that there feem- 
“ eth to be left only the fkin covering the 
“ bones. 
<e Also it is manifeft, that diverfe of 
** thofe which have been opened after 
Ci death, have had their livers utterly rot- 
“ ted ; others have had their livers fwolne 
<f to an exceeding greatnefle; fome, the 
fpleene extreamly fwolne; otliers have  APPENDIX, 
206 
“ been full of water; others have had the 
<c lungs putrified, and flunk whilfl they 
“ have lived. 
“ These and diverfe other fignes, too 
<e many for to be mentioned here, do af- 
*e flidt poore feamen, which are often pafl 
“ man’s helpe, in fuch time and place as 
“ they happen; the cure whereof only 
<c refleth in the hands of the almightie.” 
After mentioning Ectbius and Vierins 
as writers on the difeafe, and taking notice 
of the indications of cure as laid down 
by them, he fays, “ he may fpare his 
“ labour, in writing what broths or 
“ herbes can ferve befl, where no frefhe 
“ food can be gotten He therefore goes 
on to direct the ufe of fuch things as are 
ufually carried to fea; namely, <e wine, 
<£ fugar, fpices, and other comfortable 
“ things, which the chirurgeon ought to 
** take care that the men have in due fea- 
tc fon ; and, moreover, he ought, morn- 
“ ing and evening, to feeke for poore and 
cc weake men in their cabins, or, fo foone 
“ as they are miffing at their meffies, to 
“ enquire for them, and fee that their ca- 
4< bins be fweet, and their provifions ac- 
“ cording. APPENDIX. 
207 
<e And whereas the fifft part of this 
“ cure is in opening obflru&ions, it is 
“ therefore fit, in the beginning of the 
“ griefe, to give an opening clyfler then 
the next day, if the party be ftrong, 
“ open a veine ; but beware, as is faid, of 
“ taking away too much blood at once.” 
If the difeafe be attended with fwelling 
and fullnefs, he advifes a purge, and then 
orders to make the patient, fome comforta- 
ble fpoon-meat, namely, “ an oatmeal 
“ caudle, with a little beer or wine, the 
te yoke of an egge, and fome fugar; or a 
*€ broth, made with currants or other 
“ fruite, with fpices and fugar; and, for 
<c drink, barley water, with fome juice of 
“ lemons, if it may be had, if not, with 
(( oyle of vitriol and fugar. 
“ The juice of lemons is a precious 
“ medicine, and well tried, being found 
(i and good ; let it have the chief place, 
“ for it will well deferve it. It is to be 
“ taken twice a-day, a fpoonful or two 
“ with fugar.” In want of it, or the 
the juice of limes, oranges, or citron, or 
the pulp of tamarinds, give <c oyle of vi~ 
“ triol, as many drops as will make a cup 
“ of beer or water fower a little, as it  APPENDIX. 
“ were, and add fugar, or fome fyrup i A 
“ decoCtion of bifket, and therein alm6nds 
“ ground, with fugar, and a little 
“ mon or rofe-water, is a very comforta- 
ble drink to be taken now and then to 
te refrefh the flomach.” 
He proceeds then to give directions how 
to fweat the patients, and how to relieve 
extreme coftivenefs -y next, he directs lo- 
tions for the rotten gums, and orders the 
fwelled limbs to be fomented with a weak 
lixivium, boiled up with fome of the dif- 
cutient and warmer kind of herbs, and af- 
terwards to be rubbed with particular oint- 
ments that he mentions. 
In the cure of fcorbutic ulcers, he re- 
marks, that “ until the obftruCtions in the 
“ liver and fpleene, be removed, thefe 
“ ulcers give no place to good healing f 
and therefore advifes “ all fharp and vio- 
“ lent medicines to be fhunned, and no- 
“ thing but foft and anodyne things to be 
“ applied, for otherwife, you will not only 
“ flrive againft the flreame, but put your 
“ patient to needlefs difquiet, and thereby 
" increafe his difeafe. 
“ A poultice of bifket, boiled up in 
(C beere or wine, applied warm, will won- APPENDIX. 
209 
“ derfully comfort a weak limb, and af- 
“ fwage pain : But fattie things muft be 
“ forborne in fome cafes; namely, when 
“ the pain is (harp and quick, left you 
“ caufe putrefadion and fuppuration of 
(t the humours againft your will; yea, 
<c and rather ufe acetous medicines and 
" anodynes.” 
This extrad ftiews that JVoqdall was a 
man of fome obfervation. 
There are many good things for the 
time he wrote. In other parts of his book, 
his method of treating wounds, both com- 
mon and gun-fhot, was judicious and Am- 
ple ; his dreftings being, for the moft part, 
very plain, chiefly dry lint, and he con- 
demns the ufe of tents and efcharotic ap- 
plications. 
With regard to fradures, he was an 
enemy to long rollers, or tight bandages. 
When he amputated, he often made 
ufe of the crofs-ftitch, to keep down the 
flefti over the end of the flump ; and he 
knew how to reftrain the bleeding, by ty- 
ing the veflels. 
He was the inventor of the t7~cjine> 
which he fo named from its three extremi- 
ties, (a tribus finibus) each ferving a dif- 210 
APPENDIX. 
ferent purpofe; and he was the Aril man 
who introduced the enemata fumofa * ; pro- 
pofing alfo to throw up, in this manner, 
powders, and the like, into the inteftines, 
in order to cure obftinate fluxes, and other 
difeafes of thofe parts. 
* It may not be amifs in this place to inform the 
reader, that I have found, upon trial, that tobacco-fmokey 
thrown up in the way of clyfter, effectually and imme- 
diately deftroys the afcarides. And this I was induced 
to try upon the recommendation of Mr. Turner, fur- 
geon, at Liverpool. See his letter to Dr. Fothergilly in 
the fecond volume of the London Medical Obfervatiant, ESSAY V. 
O N T H E 
DISSOLVENT POWER 
Q F 
Q.UICK-LIME. ‘There are agents in nature able to make the 
p articles of bodies flick together by very 
flrong attractions; and it is the bufenefs of 
experimental philofophy to find them out. 
Newton* ESSAY V. 
ON THE 
Diss olyent Power of Quick- 
Lime. 
TH E experiments of the fecond and 
third eflays have fufficiently ihewn, 
that the cohefion of animal and vegetable 
fubftances depends immediately on the fixed 
air ; but how far the influence of this 
. principle extends into the mineral king- 
dom, is not yet certainly known. 
HALLER feems to think that it is 
very general, being here alfo the 'vinculum, 
or gluten verum moleculis terreis adunandis *; 
though it does not appear that he has any 
adtual experiment of his own to confirm 
this hypothefis. 
But fince the publication of Dr. Black's 
moft ingenious paper on the magnefia, we 
* Prim. Lin. fe& 244. 214 
On the Dissolvent 
cannot help being convinced that the the- 
ory holds good, at leaft with regard to the 
clafs of bodies which he hath examined; 
to wit, the calcareous earths. 
The reader may remember, that the 
dodtor’s theory of calcareous earths is, that 
thefe bodies have a very ftrong degree of 
affinity * with fixed air, and, in a natural 
ftate, are replete with it; that by calci- 
nation they are deprived of this element, 
and hence become cauftic and Ibluble in 
water but that, upon reftoring the fixed 
air, they are again rendered mild and in- 
foluble. 
All this is very fatisfadtorily fhewn in 
the effay above-mentioned; but it occur- 
red to me, that it might pofiibly be ftill 
further proved, and that in a way which 
would afford an ocular demonftration. I 
thought that perhaps the diffolved quick- 
lime might be rendered vifible, and would 
precipitate upon transferring fixed, air into- 
lime-water “f*. 
* And fixed air has a ftronger affinity with calca- 
reous earth than with any other fubftance yet known. 
t In the manner described in the fecond eflay, and 
xoth experiment. Power of Quick-Lime* 
EXPERIMENT i. 
I presently fet about the experiment, 
and found it anfwer fully to my expecta- 
tions i for the lime-water, which was fil- 
tered, and perfectly limpid, became tur- 
bid in a few minutes after the effervefcence 
began, and that the air which was extri- 
cated from the mixture of acid and alcali, 
had paffed over into the phial containing 
it. And it was highly pleafing to fee the 
particles of the quick-lime, which, but 
When I found that by transferring air into different 
bodies, a variety of curious changes were produced, I 
laid afide the glafs tube, and had an apparatus prepared 
which rendered the performance of the experiments 
more eafy. I caufed a metal tube to be fixed on by a 
fcrew to the neck of a phial, as reprefented in fig. IV, 
which tube could be occafionally inferted into the 
mouth of another phial, being previoufly w’ound about 
with foft leather, in order to prevent the efcape of the 
fa&itious air. 
But a very ingenious friend, who is remarkable for 
his fkill in every part of natural philofophy, but parti- 
cularly mechanics, improved it further, by contriving 
the machine in fig. V. In the neck of the bottle A, 
which is the recipient, there is an air-valve, which al- 
lows the air to pafs into the bottle, but prevents its 
return j and this I found greatly to fhorten and facilitate 
the procefs. 216 
On the Dissolvent 
two or three minutes before, were quite 
invifible, and diffolved in the water, all 
running together, and falling to the bot- 
tom, having returned to their original ftate 
of infolubility, the moment they were fa- 
turated with the fixed air. 
When the turbid mixture had flood 
long enough to allow the precipitate all 
to fubfide, I poured off the clear, and 
found fome grains of calcareous earth, 
which effervefced violently with fpirit of 
vitriol. * 
And thus was the theory of Dr. Black 
placed beyond the reach of contradiction; 
fince we muft here be convinced, from 
what is feen to pafs before our eyes, that 
the quick-lime became foluble in water 
from the want of its fixed air, becaufe we 
find it grow infoluble the moment the ce- 
menting principle is reftored. 
Finding, by the preceding experiment, 
that the lime, though fo minutely divid- 
ed, and fo intimately mixed with the wa- 
ter, as to be reduced to a ftate of aCtual 
fluidity, might neverthelefs be rendered 
folid, and brought immediately into view, 
by reftoring the cementing principle, I be- 
gan to think, that, by introducing air into Power of Quick-Lime. 
217 
the natural fulphureous waters, as I had 
done into the lime-water, the fulphur 
might be rendered vifible, as I conceived 
that this diflolution of the fulphur poflibly 
may be brought about in thefe waters, 
from its being fome way or other deprived 
of its fixed air. 
But as I could not immediately pro- 
cure a natural fulphureous water, I re- 
folved to try the experiment with an arti- 
ficial one. 
EXPERIMENT 2. 
In order to do this, I boiled up fome 
flowers of fulphur with water and quick- 
lime (as directed for preparing the ful- 
phur prcecipitatum), and having filtered 
the folution, which made it perfectly tran- 
fparent, I put about four ounces of it 
into the phial ufed in the foregoing ex- 
periment, and transferred the air from an 
efFervefcent mixture contained in the other 
phial. 
The fulphureous did not fo foon lofe its 
tranfparency as the lime-water, but, in 
eight or ten minutes, a fcum formed on 
the furface; and the whole folution imme- 
diately after becoming turbid, I could 218 
On the Dissolvent 
plainly perceive the folid particles collect- 
ing themfelves together. 
When I thought that there was a fuSH- 
cient quantity of air thrown in, the phials 
were feparated, and the turbid contents of 
the firSt one poured into a tall drinking- 
glafs. The liquor now fent forth the 
Strong and peculiar fmell which folutions of 
fulphur always yield, when an acid is added 
to them. 
EXPERIMENT 3. 
Having foon after got fome bottles of 
the Lucan water *, a few ounces of it were 
put into the phial, and air transferred from 
an effervefcent mixture, as in the two pre- 
ceding experiments; but notwithstanding 
a flight degree of milkinefs appeared at 
firit, yet no precipitation enfued. 
These experiments, however, pointed 
out a method of making a pure folution 
of fulphur, which being diluted to the 
proper degree, gives an artifical Sulphure- 
ous water, perfectly refembling the natu- 
ral, as to tafte, fmell, tranfparency, and 
* Lucan is a village within fix miles of Dublin, where 
there is a fpring of fulphureous water. Power of Quick-Lime. 
219 
want of colour, and not liable to grow 
turbid on the addition of acids, which all 
other artificial folutions of fulphur, hitherto 
known, conflantly do. 
The turbid folution of lime and ful- 
phur, as hath been already mentioned, was 
poured into a tall glafs, and happening not 
to be thrown out, I found, after handing 
thirty-fix hours, that it did not become 
limpid, though I could plainly perceive 
a quantity of lime lying at the bottom, 
while the yellowing fluid remaining above, 
evidently fhewed to be an equable and 
true folution of fulphur, now left per- 
fectly alone in the water : I immediately 
law that there was nothing more to be 
done here than dilute this folution to a 
proper degree, and that it would then con- 
hitute a true fulphureous water. 
EXPERIMENT 4. 
Upon trial, it actually did fo; and al- 
though. this prefent folution, from being 
fo long expofed to the open air, had loft 
much of the ftrong and peculiar fulphure- 
ous fmell, yet I found, on repeating the 
experiment, that a folution, frefh-made, 
and the lime, immediately feparated from 220 
On the DissolvExNT 
it by the introduction of air, and then di- 
luted, fo as to leave the liquor colourlefs 
and tranfparent, yielded a water fo nearly 
refembling the latter, that, as to fmell, 
tafte, or appearance, it was hard to per- 
ceive any difference. 
But upon dropping lixivium tartari into 
the artificial water, it inftantly grows tur- 
bid * } whereas, when the like addition is 
made to the natural fulphureous waters, 
their brightnefs is improved ; which fhews 
that the folution of fulphur, in the natu- 
ral waters, is brought about in fome man- 
ner not analogous to that in the artificial; 
for it feems pretty obvious, that the ful- 
phur is here rendered foluble in water, 
from being deprived of its cementing prin- 
ciple by that fhare of the quick-lime 
which remains undiffolved in the boiling. 
This prefented a new theory concerning 
the folubility of oil, when combined with 
* On mixing the fixed alcali with the fulphureous 
water, the peculiar fulphureous fmell is inftantly 
changed to one which is rather more difagreeable, and 
though the mixture becomes turbid, yet no precipita- 
tion enfues; the fulphur and the alcali, joining into a 
body, feparate themfeives from the water, and remain 
fufpended in the glafs. Power of Quick-Lime. 
221 
the cauflic alcali, and made into foap; 
which, I conje&ured, might, as well as 
the fulphur, be rendered mifcible with 
water, when, the cohefion of the oily par- 
ticles is deftroyed, by the lofs of their 
fixed air. 
EXPERIMENT 5. 
This conje&ure was found to be right, 
by transferring air, from an effervefcent 
mixture, into a folution of common foap ; 
for the moment the air mixed with the fo- 
lution, the oily part began to feparate, and, 
in a few minutes, all rofe to the furface, 
the cementing principle now being reftored 
to the difunited particles of the oil. 
I repeated this experiment on a folu- 
tion of foap, which was filtered, and kept 
above a week after it was made ; fo that 
there could be nothing of a fpontaneous fe- 
paration in either cafe. 
These experiments opened the way to 
fome improvements in pharmacy ; fince it 
followed plainly, that if oil was thus ren- 
dered mifcible with water, camphor, and 
all kinds of rejinous bodies, might, in like 
manner, be dilfolved. On the Dissolvent 
222 
EXPERIMENT 6. 
I began with the camphor, and hav- 
ing rubbed a drachm of it with an equal 
portion of quick-lime, and then poured oil 
fix ounces of lime-water, I allowed the 
mixture to ftand for half-an-hour, that 
the grofs and infoluble part might fubfide; 
the clear was then pafied through a filter, 
and found to be a ftrong folution, contain- 
ing at leaf! one half of the camphor. 
On another occafion, I made ufe of 
heat, boiling the camphor and quick-lime 
with water in a clofe vefiel, and thus ob- 
tained an entire folution. 
These folutions, when filtered, are per- 
fectly limpid, and never part with the 
camphor; for though the lime may be 
precipitated in feveral ways, yet I have not 
hitherto hit upon any method of feparating 
the camphor from the water. 
Common fait, if added in a large pro- 
portion to the folution, throws up a cream 
to the furface, which, upon examination, 
is found to confifl of little more than mere 
calcareous earth. 
And ardent fpirits, though they caufe a 
milkinefs when added to the folution, do Power of Quick-Lime. 
223 
not entirely part the camphor from the 
water. 
EXPERIMENT 7. 
Myrrh, gum guaicum, afa fcztida, aloes, 
cajlor, balfam of T'olu, with majiicb, jalap, 
and the cortex, were all tried in the fame 
manner as the camphor, and were found to 
yield ftrong folutions and tin&ures, the 
lime appearing to take up the fame part of 
thefe fubflances that is diffolved by the 
means,of ardent fpirit. But thefe aque- 
ous tinctures muft be much more elegant 
medicines, and perhaps may be found more 
efficacious than the fpirituous ones, on 
account of the extremely minute divilion 
of their more adtive part, as well as their 
convenient exhibition, fince they will never 
become turbid, or feparate, on being mixed 
in any watery vehicle. 
There is as much lime in all thefe tinc- 
tures and folutions, as there would be in 
the like quantity of lime-water, which 
bids fair to improve the virtues of fome of 
them, and can do no great injury that I 
know of to any; but if it ffiould ever be 
thought fo, the lime may be precipitated 
from them, by throwing in air from fome 224 
On the Dissolvent 
effervefcent mixture, as hath been already 
explained. 
The air, when thus thrown in, renders 
the folution, or tincture, quite turbid, and 
appears plainly to the eye, at firft, to re- 
unite the dififolved particles of the refin, as 
well as the lime; but the former are very 
foon re-diflolved, and the lime only falls to 
the bottom. 
As the fixed air, when thrown off by 
putrefaction, or during the firft ftage of 
fermentation, equally produced the effeCt, 
of rendering mild the caujlic alcali, with 
that which was fet free by effervefcence, 
it might have been fairly concluded, that 
it would alfo precipitate the lime from 
lime-water but as I had laid it down for 
a rule to depart as little as pofiible from 
aCtual experiment, and to be very fparing 
in drawing conclufions from any thing but 
evident faCts, I determined to make the 
trial. 
E X PER E M ENT 8. 
Accordingly, having joined two 
phials together, by means of the bended 
glafs tube, (as in the 17th experiment of 
the fecond effay), and filled one with frefh Power of Quick-Lime. 
225 
mutton, and a little water to make it pu- 
trefy the fooner, and the other with lime- 
water, I laid them by in order to let the 
putrefaction proceed. 
Before twenty-four hours were elapfed, 
the precipitation of the lime was evident, 
and it increafed every day, for fix days 
that the phials remained in this fituation; 
but lhaking the phials one day, in order 
to make the putrid liquor fubfide (for it 
rofe in the tube in the fame way that it 
did in the experiment before-mentioned, 
when I was transferring air from putrid 
fiefh into the cauftic alcali), the tube hap- 
pened to break, and an end was thereby 
put to the experiment; but I had feen 
enough to prove thatfixed ah', when thrown 
off* by putrefaftion, would produce the very 
fame effedt on lime-water with that which 
was fet free by efiervefcence. 
And here we have an additional proof 
of the fixed airs being the ce?nenting prin- 
ciple in animal fubfiances; fince we feet 
that while the flelh is refolved, and falls 
in pieces, from the lofs of this principle, 
the lime is rendered folid by having it re- 
ilored. 226 
On the Dissolvent 
While this experiment, and the follow-* 
ing, were going on, I filled two phials 
with filtered lime-water (that ufed in the 
experiments was always filtered), and left 
one of them without a cork, while the 
other was clcfely flopped, and laid them 
by as flandards ; to fee if any, and in what 
proportion, the lime would precipitate 
when left to itfelf: But neither the one, 
nor the other, in a fortnight’s time, depo- 
fited the fmallefl particle of lime. 
EXPERIMENT 9, 
In order to try the effedls of the gas, or 
vapour, difeharged during the firft Rage of 
fermentation, I made up fix ounces of a 
fermentative mixture, of rlefh meat, bread, 
'cabbage, and turneps, with the requifite 
quantity of water, and put it into one 
phial; which being joined, by means of 
the tube, to another filled with lime-wa- 
ter, the two were placed in a temperate de- 
gree of heat, that the mixture might fer- 
ment the fooner. 
The fermentation began in the ufual 
time, and went on with the common ap- 
pearances : And as it did proceed, the 
lime became every day more and more vi- fible j and forming, firft, light flakes of a 
feathered refemblance, near the furface, 
thefe gradually fell to the bottom, until, 
at the end of five days (the period that the 
phials remained in conjundion) when I 
poured out the water, and allowed the pre- 
cipitate all to fubfide, I collected three 
grains of calcareous earth from fix ounces 
of lime-water, which was the quantity 
contained in the phial. 
This addon of the vapour (which, oil a 
former occafion, was termed antifeptic) in 
re-uniting the difiblved and fcattered par- 
.tides of lime, may ferve to give fome idea 
of the manner of its operation on diflolved 
blood, when the texture of that fluid is de- 
firoyed and broken, by a putrefadive 
acrimony. 
And this experiment like wife {hews, 
that lime-water, when given as a lithon- 
triptic, ought not to be drank at meals* 
left it lofe part of its virtue, from the fixed 
air of the alimentary fubftances faturating 
and rendering inert, the difiblved and ac- 
tive particles of the quick-lime. 
The adivity of lime-water muft alfo be 
impaired by infufing vegetable fubftance9 
therein, which contain much fixed air 3 
Power of Quick-Lime. 228 
On the Dissolvent 
fuch as the guaicum, or fafafras ; for thefe 
woods abounding in refin, give out their 
cementing principle, which, uniting with 
the diffolved quick-lime, reftores it to its 
original ftate of an inactive calcareous earth: 
Therefore, when it is intended that thefe 
woods, or any other fubftance of the like 
nature, fhould give out their virtue to lime- 
water, and that the water fhould, at the 
fame time, contain its due proportion of 
diffolved lime, fome quick-lime ought to 
be added, during the time of maceration. 
We have feen, then, in three different 
inflances, that the lime is precipitated from 
lime-water by reftoring to it the fixed air: 
May not lime-water, therefore, upon this 
principle, be ufed as a tefi to try whether 
or not bodies contain fixed air ? If any 
body, upon mixture with lime-water, oc- 
cafions a precipitation, and if the precipi- 
tate fo caufed effervefceth with acids, may 
we not conclude that the body fo added 
contains fixed air; and that, in a greater 
or fmaller proportion, as the precipitation 
of the lime from the water is more or lefs 
immediate ? Power of Quick-Lime. 
229 
EXPERIMENT 10. 
Spiritus cornu cervi per fe, fait of 
hartfhorn, and fait of tartar, being feve- 
rally mixed with lime-water, immediately 
threw down a precipitate, which, upon 
examination, was found to be true calcare- 
ous earth. 
EXPERIMENT 11. 
Spirit of fal ammoniac, made with 
quick-lime, and the caujlic ale aline ley, made 
of pot-afh and quick-lime, when mixed 
with the lime-water, did, neither of them, 
in the lead: dedroy its tranlparency, nor did 
any precipitation ever enfue. 
EXPERIMENT 12, 
But air being transferred into the fame 
caudic alcalies, and lime-water then mixed 
with them, the fame appearances followed 
which happened upon mixing the mild al- 
calies in the 10th experiment, 230 
On the Dissolvent 
EXPERIMENT 13. 
Brown fugar*, when mixed with lime- 
water, prefently threw down a precipitate, 
which effervefced violently on the addition 
of fpirit of vitriol ; but refined fugar (which 
is deprived of great £hare of its fixed air, 
by the quick-lime that is ufed in refining 
it), when diffolved in lime-water, did not 
at all defiroy its tranfparency, and, after 
Handing twenty-four hours, threw down 
fcarce any precipitate. 
EXPERIMENT 14. 
Recent juices of fruits, or other vege- 
table fubffances, when mixed with lime- 
water, deHroyed its brightnefs immedi- 
ately, and loon after threw down a preci- 
pitate, which effervefced violently on the 
addition of fpirit of vitriol. But fermented 
liquors occafioned no immediate change, 
nor did any precipitation enlue until after 
feveral hours Handing, and this different 
* Dr. Hales found the proportion of air, in the 
eoarfeft fugar, to be a little more than one-tenth of the 
whole. See his 65th experiment of the ift vol. Power of Quick-Lime. 
231 
in different liquors *: Then, alfo, the 
quantity of precipitate was but fmall, the 
whole of the lime not being faturated, as 
the tafle plainly tefiified was done by the 
recent, unfermented juices. 
EXPERIMENT 15. 
Ardent fpirits -f* produced dill lefs al- 
teration on lime-water, than the fermented 
liquors; but they abforbed the air from an 
effervefcent mixture very greedily, and, 
when thus charged, threw down the lime 
from the lime-water inftantly on being- 
mixed therewith. 
These experiments all concurring to 
edablifh lime-water as a tejl of the pre- 
fence, or abfence, of fixed air, I refolved 
to examine fome of the animal fluids, in 
this manner. 
In Dr. Whytt's very ingenious effay on 
the virtues of lime-watar, we find a num- 
ber of experiments, made with a view of 
determining what things impair or deflroy 
its diffolvent power, with regard to the 
* Cyder and bottled beer threw down the precipitate 
much fooner than claret or port-wine. 
+ It was re&ifted fpirit that was tried, 232 
On the Dissolvent 
calculus ; one of which plainly fhews, that 
the urine contains fixed air ; for when this 
celebrated profeffor mixed 44 an ounce and 
44 a half of lime-water, and an ounce of 
44 frefh-made urine, it immediately loft its 
44 yellow colour, and became whitifh and 
44 turbid, and, in a little time, a light, 
44 white fediment fell to the bottom, and 
44 left the liquor above perfectly pellucid, 
44 of a fine light lemon colour, without 
44 any fcum or cruft on the fides of the 
44 glafs 
EXPERIMENT 16. 
I repeated this experiment with pre- 
cifely the fame appearances j and found, 
that on pouring off the clear, and dropping 
in fpirit of vitriol, a violent effervefcence 
enfued j plainly fhewing, that the parti- 
cles of the quick-lime, now faturated with 
the fixed air, which they had abforbed 
from the urine, were returned to their ori- 
ginal flate of a calcareous earth. 
We have already hinted, that there is 
fome danger of lime-water’s being deprived 
of part of its virtue, from the vapour arif-r 
9 See the Eflay, fesSt. 2, No. 8. Power of Quick-Lime. 
233 
ing from the alimentary fubftances, during 
their fermentation in the firh paffages; and 
here we have another circumftance which 
is difcouraging, with regard to the diffolu- 
tion of the calculus. By the experiments 
hitherto made, the calculus appears capa- 
ble of diflolution in two ways ; either by 
means of a ftrong acid, fuch as fpirit of 
nitre, which probably a&s immediately 
on the earthy part of the ftone, or by lime- 
water, or cauftic alcali, abforbing the 
fixed air; whence the earthy parts, de- 
prived of what bound them together, 
muft prefently fall to pieces *. 
With regard to internal exhibition, the 
acid is entirely out of the queftion, and the 
only hope of a fafe diffolvent mud: reft on 
the caujlic alcali, or on the lime-water. 
This alcali, when combined with oil, 
and made into foap, is not only fo greatly 
obtunded thereby as to lofe much of its 
power, but the foap itfelf is fo naufeous, 
that few patients can bring themfelves to 
* Of all the various fubftances examined by Dr. 
Hales, with a view of determining their refpedbive quan- 
tities of air, the human calculus was found to contain 
the largeft proportion j above one half of this mafs con- 
lifting of fixed air. 234 
On the Dissolvent 
take it in a quantity fo large as to prove of 
much effed; it would therefore be a happy 
difcovery if any vehicle could be found out, 
that would fufficiently fheath the acrimony 
of the cauftic alcali, fo as to allow it to be 
taken in large and continued dofes : Poffi-- 
bly, veal broth, or a decodion of marfli- 
mallow roots, might be found to anfwer 
this purpofe; and lime-water might be 
taken at the fame time, which would not 
at all interfere with the operation of the 
alcali, but rather add to its adivity. 
Lime-water, when taken alone, mud 
often fail in producing any confiderable ef- 
feds as a lithontriptic, becaufe it mulf lofe 
much of its power, not only from the va- 
pour it meets with in the firft paffages, but 
likewife from the fixed air of the urine it- 
felf, which muff faturate great fliare of the 
quick-lime, even when it hath reached 
the bladder. 
That this adually happens, may be 
inferred from the great quantity of earthy 
matter difcharged in the urine of perfons 
who are under a courfe of lime-water ; 
this fediment feeming to confift moftly of 
lime, parted from the water in which it Power of Quick-Lime. 
235 
was diffolved, being precipitated by the 
fixed air of the urine. 
It fhould feem, then, as if the cauftic 
alcali bade the faireft for fuccefs in thefe 
cafes and therefore its effects fhould be 
tried in hofpitals, and, as hath been al- 
ready mentioned, it fhould be given in 
fome gelatinous, or mucilaginous vehicle, 
that would fheath the fharpnefs of the fait, 
in fuch manner as to allow of a confidera- 
ble quantity being taken ; which certainly 
might be accomplifhed, fince we find that 
Dr. Jurin brought himfelf, by degrees, to 
take an ounce and a half of capital foap 
lees, in the courfe of a day, though diluted 
by liquors that had little or nothing of the 
mucilaginous nature*. 
* There is a paper in the Gentleman’s Magazine 
for O&ober 1763, which proves very plainly, that a 
noftrum, exhibited by one Dr. Chittick, and which is 
found, after a perfeverance of fome months, adlually to 
diflolve the ftone, is nothing more than the cauftic al- 
cali, given in veal-broth. The patients prepare the 
broth themfelves, and fend it to the do£tor every day, 
$vho returns it with the medicine mixed therein. 236 
On the Dissolvent 
EXPERIMENT 17. 
The perfpirable matter alfo contains 
fixed air: Three ounces of filtered lime- 
water being put into a phial, and a funnel 
fixed clofe into the neck of it, I blew in 
my breach through the funnel, and by the 
time I had continued fo doing for ten or 
twelve minutes, I found the water grow- 
ing turbid, and the lime becoming vifible. 
This being a tirefome kind of opera- 
tion, I defifted, when I had thoroughly 
fatisfied myfelf that the perfpirable matter, 
if thrown in in a fufficient quantity, would 
faturate all the lime, fince even what I had 
done was found, upon collecting the pre- 
cipitate, to have thrown down more than a 
grain. 
I found alfo that fweat contains fixed 
air, and ufed the following method of 
collecting fome drachms of this fluid. 
EXPERIMENT 18. 
Having often obferved hackney-chair- 
men fweat fo profufely after fetting down 
their fare, that they fweep it off from their 
bare heads in a full ftream with their 
leathern {traps, I took an opportunity one Power of Quick-Lime. 
237 
day of collecting about a couple of drachms 
of fweat, that had been raifed in this man- 
ner, and having mixed it with fix drachms 
of lime-water, found that the mixture im- 
mediately became turbid, and, in a fhort 
time, depofited a light fediment, fuch as 
was thrown down from the urine, and 
which effervefced as violently when fpirit 
of vitriol was added. 
I had formerly ventured to aflert, that 
air is thrown off from the fluids by perfpi- 
ration, and thefe experiments, I appre- 
hend, will readily be allowed as proofs of 
the truth of that aflertion. 
But the faliva leems as if it contained 
little or no fixed air ; for when Dr. Whytt 
infufed a piece of human calculus, weigh- 
ing three grains, in a mixture offaliva and 
lime-water, in the proportion of one of 
the former, to two and a half of the latter, 
in two days warm digeftion, the bit of 
calculus was reduced to one grain and a 
half*. 
That is to fay, the lime-water having 
loft fcarce any thing of its power, the cal- 
culus diflolved as readily, in a mixture of 
* Se£t. 4. No. 2i. 238 
On the Dissolvent 
faliva and lime-water, as it would have? 
done in lime-water alone, equally dilute * 
for had the faliva abounded in fixed air, 
which would have faturated the quick- 
lime of the water, its diffolvent power 
would have been proportionably weakened, 
as we find it was by mixing frefh vegeta- 
ble juices, or honey, with lime-water*. 
EXPERIMENT 19. 
Two drachms of faliva being mixed 
with fix drachms of lime-water, the mix- 
ture did not grow turbid ; but in two 
hours I found afediment, which, on pour- 
ing off the clear, and dropping in fpirit 
of vitriol, fhewed little or no fign of ebul- 
lition. Hence I concluded, that this fe- 
diment was fcarce any thing more than 
the grofs part of the faliva, which, when 
left to itfelf, in a little time depofites a 
confiderable portion of thick and vifcid 
matter. 
* See Dr. IVhytt's Eflay, fe£t. 6 7, No. 34,36, 37, Power of Quick-Lime. 
239 
EXPERIMENT 20. 
I therefore refolved to repeat the 
experiment, and having colle&ed near 
an ounce of faliva, and fufFered it to ftand 
long enough for the thick part to fub- 
lide, I then mixed two drachms of the 
clear with fix drachms of lime-water, 
and found it produce no immediate al- 
teration. 
But two drachms of the fame clear 
faliva being put into a fmall phial, and 
air transferred into it from an effervef- 
cent mixture, and then mixed with fix 
drachms of lime-water, inftantly the mix- 
ture became turbid, and a large quan- 
tity of precipitate, in the form of flakes, 
fell to the bottom, and effervefced vio- 
lently when fpirit of vitriol was poured on 
it. 
The firft mixture of lime-water and 
faliva, after fianding twenty-four hours, 
was covered with a cruft, and found to 
have depofited but a fmall quantity of 
whitifh vifcid matter, which effervefced 
but flightlv with the acid fpirit.  On the Dissolvent 
240 
So that the faliva naturally contains very 
little fixed air, but, neverthelefs, is a pow- 
erful abforbent thereof*. 
From another experiment of Dr. 
Whytt’s, the bile appears to contain as lit- 
tle fixed air as the faliva; for when he 
immerfed a fragment of calculus, weighing 
three grains, in an ounce of cyflic bile, 
and three ounces of oyfter-fhell lime-wa- 
ter, and kept it in a moderate heat for 
forty-two hours, he found that near a 
grain and a half of the fubftance of the 
calculus was diffolved in the form of thin 
whitifh fcales ‘f*. 
* We had a former proof of the affinity between fa- 
liva and fixed air, in the 14th experiment of the fecond 
efiay ; wherein it was found that the faliva, when inti- 
mately mixed with an animal fubftance, has fome de- 
gree of antifeptic power; which agrees with the gene- 
ral theory concerning this power, as laid down in the 
third efiay : For faliva, being an attra&er of fixed air, 
when mixed with an animal fubftance, unites itfelf 
with the fixed air of that fubftance, and in this man- 
ner reftrains, for fome little time, the. flight of the ce- 
menting principle. 
+ Se&. 4. No. 27,s Power of Quick-Lime. 
241 
EXPERIMENT 21. 
As I could not, at this time, procure 
any frelh human bile, and excepting it 
were frefh, and taken from a healthy fub- 
jecft, the experiment would not have been 
fairly made, jl was obliged to try that of a 
dog : One of thefe animals being therefore 
killed, and its gall-bladder taken out, about 
a drachm and a half of bile was found in 
the cyft. 
One half of this quantity being mixed 
with three drachms of lime-water, the 
mixture remained tranfparent, and equa- 
ble, for an hour; it then loft its pellucidi- 
ty, and gradually depoftted a light fedi- 
ment, of dark yellow, or rather orange 
colour. When it had ftood twenty-four 
hours, I pafled the mixture through a fil- 
ter, in order to leparate the fediment; 
which being done, fpirit of vitriol was 
poured on, and found to raife a flight de- 
gree of effervefcence. 
The other half of the bile was put into 
a fmall phial, and air transferred into it 
from an effervefcent mixture, as had been 
done in regard to the faliva, and then it 242 
On the Dissolvent 
was mixed with three or four drachms of 
lime-water. 
There was very little difference be- 
tween the appearances of this mixture, and 
thofe of the former ones: It remained 
tranfparent for about the fame fpace of 
time, and then, like the other, loft its 
brightnefs by degrees, and depofited a fe- 
diment, which only differed in regard to 
the colour, being of a more light yellow. 
When this fediment was examined, after 
Handing twenty-four hours, it was found 
to effervefce violently with the acid, 
whereas the ebullition of the other fedi- 
ment was but obfcure. 
From thefe experiments (if the lime- 
water be a true teft) we fee, that bile con- 
tains fomewhat more fixed air than faliva, 
and does not abforb this element fo pow- 
erfully *. 
And here we plainly fee in what fenfe 
thefe fluids are to be called faponaceous y 
* As the bile, in a found fate, contains fo little fixed 
air, we immediately fee the reafon why putrid bile, or 
the fpirit diftilled from it, raife little or no ebullition 
with acids, notwithftanding the other marks of the al- 
cali in that fluid. Power of Quick-Lime. 
243 
and may likewife comprehend in what 
manner they perform their action of dif- 
folving fat, or oily matters: They abforb 
the fixed air from the oils expofed to their 
action, and thus deflroying the bond of 
union between the oleofe particles, render 
thefe bodies mifcible with water. 
And hence the obvious reafon, why the 
faliva fhould be the more powerful abfor- 
bent of the two ; for had not the oily part 
of our food, from its admixture with the 
faliva in maftication, been rendered mifci- 
ble with the watery part, the alimentary 
mixture could not have fermented properly 
when received into the ftomach; the con- 
fequence of which would been licknefs, 
naufea, and heartburning *, from the 
fharpnefs of the oil, now become rancid by 
the mere heat of the place. 
But when all the difcordant parts of 
the alimentary mixture are blended toge- 
ther, by the diifolvent power of the fialiva, 
and further united by the fame quality in 
the fuccus gafiricus, bile3 and pancreatic 
* Not the heart-burning attended with that 
accompanied with nidorofe, eru&ations. 244 
On the Dissolvent 
juice *, then no reparation of oil enfues, 
but the fermenting motion goes on, kindly 
and regularly, until new combinations take 
place, and that every particle of the food 
is broken and changed. 
But in fome conftitutions this abforbent 
power of the digeftive fluids is fo greatly 
weakened (or, in other words, they con- 
tain much fixed air, when, in a natural 
and healthy fiate, they ought to contain 
very little), that the oily part of the food 
is never thoroughly mixed, or fubdued; 
and hence the immediate caufe of indigefii- 
on, cardialgia, rancidity in the fiomach, 
and extraordinary flatulence. 
And pofiibly this might appear, upon 
examining the faliva of the patient, by 
mixing it with lime-water : If the mixture 
fhould immediately become turbid, and 
depofite a fediment that fhould effervefce 
on the addition of an acid fpirit, it would 
fhew the morbid fiate of the faliva, as 
* Though neither the fuccus ga/lricus, nor pancrea- 
t/ais} were tried, with relation to their containing fixed 
air, yet I apprehend that their fimilitude to the faliva 
will make it no unfair inference to fay, thatthefe fluids 
contain very little of this element. Power of Quick-Lime. 
245 
containing too great a proportion of fixed 
air, which muft necelfarily hinder the ab- 
forbent power of this fluid, and confe- 
quently difenable it from aiflolving the 
oily part of the food. 
I am inclined to think, that this is ac- 
tually the cafe in gouty fubjedts, where the 
complaints above-recited are conflant fore- 
runners, or attendants; and that the juices 
in thefe people are too much loaded with 
fixed air, which not only impairs the ab- 
forbent power of the digeftive fluids, but 
alfo difpofeth the earthy and faline parti- 
cles of the blood, to run into concretions, 
which obflrudt and tear the fmall veflels 
wherein they happen to be impacted. 
If this be the real condition of the 
fluids in gouty conftitutions, lime-water, 
or the cauftic alcali, would promife fair to 
be excellent antartbritics; and perhaps 
the benefits which accrue to patients, from 
the ufe of certain waters, may arife, in 
great meafure, from thefe waters contain- 
ing an earthy matter diflolved therein, 
void of fixed air, and which have an ab- 
forbent power, like what is obfervable in 
lime-water; which enables them not only 246 
On the Dissolvent 
to help digeftion, but alfo to diffolvc, in 
fome meafure, the concretions that confti- 
tute the difeafe 
* The Bath-Water, which is found to give fo much 
relief in gouty and nephritic cafes, and in complaints 
cf the ftomach, arifing from a weaknefs of the abfor- 
bent power in the digeftive fluids, though perfectly 
limpid as it flows from the fpring, yet prefently depo- 
fits a large proportion of earthy matter, and is alfo faid 
to grow turbid, and let fall a precipitate, on being mixed 
with an alcali. 
If any perfon on the fpot be deflrous of knowing 
whether this earthy matter, which is diflolved in the 
water, be void of fixed air (like quick-lime diflolved in 
lime-water), or whether it be held in a ftate of diflo- 
lution, by the intervention of an acid, let him make 
the following trials. 
I. Drop either lixivium tartari, or fpiritus cornu cervi 
ter fe, into the Bath-wrater. 
1. Drop either the caufiic alcaune ley, made of pot-af}) 
and quick-lime, or fpiritus falis ammoniaci cum calce viva9 
into the fame water; and obferve whether it becomes 
equally turbid with the latter as with the former. 
If it fliall be found to do fo, the experiments rc i 11 
fhew that the earthy matter is diflolved in the water by 
the means of an add; but if the precipitation {hall be 
found to follow only from the mixture of the mildalca- 
lies, and that the brightnefs of the water is not at all 
impaired by the addition of the caufiic, then we may be Power of Quick-Lime. 
247 
These waters may be confidered as a 
kind of natural lime-waters, containing a 
confiderable portion of earthy matter, void 
of fixed air (like the particles of quick- 
lime dilfolved in lime-water) which, as 
foon as the water comes into contact with 
bodies containing much of the cementing 
principle, this laft is attracted by the 
earthy particles which thus acquire folidi- 
ty, and form a fuccefiion of crufls, or 
layers; and it is in this manner that, I 
think, we may form a plaufible theory for 
petrification % and for the crufts that are 
allured, that the earthy matter is diflolved in Bath-wa- 
ter from being, fome way or other, deprived of its ce- 
menting principle. 
N. B. It will be necefiary to try the caujlic alcali with 
an acid, previous to the making of the experiments, in 
order to be certain that it is perfectly non-effervescent ; 
that is, void of fixed air. 
* A petrifaction that I have met with, fince writing 
the above, feems to confirm this hypothefis. 
It is a petrified mofs, wherein may be obferved, 
very diftinCtly, the feveral gradations from abfolute 
ftone to the living vegetable ; the courfe of the fibres 
being every where plain, and eafy to be traced. The 
part of the petrifaction that lay conflantly under water 248 
On the Dissolvent 
found in the pipes and veflels containing 
certain kinds of waters. 
is abfolute ftone, and is of the calcareous kind, effer- 
vefcing ftrongly with acids; in the middle part, which 
was not fo continually expofed to the adfion of the wa- 
ter, the petrifaction is incomplete; and at the top, which 
was always above water, the vegetable is ftill alive, and 
in its natural ftate. 
The well from whence this petrifadlion was brought 
being in the neighbourhood of Dublin, I fent for fome 
bottles of the water, in order to examine it. 
On dropping a little of the filtered folution o{pot-ajh 
into a glafs of the petriiying water, it immediately loft 
its brightnefs, turned milky, and, in a few hours, de- 
pofited a white fediment, which eftejrvefced ftrongly with 
fpirit of vitriol. 
The very fame appearances happened when Lixivium 
Tar tar i was dropt into the petrifying water. 
On air being-transferred into fome ounces of the pe-, 
trifying water, it loft its brightnefs, and, in twelve 
hours, let fall a fmall quantity of white fediment. 
Hence it appeared, that the petrifying water did con- 
tain an earthy matter diftolved therein, void of fixed 
which was capable of refuming the folid form, as foon 
as the cementing principle was reftored. 
Vegetable bodies, therefore, by remaining long ex- 
pofed to the a&ion of fuch kinds of waters, will have 
their fubftance gradually diftolved ; becaufe the earthy 
particles in the Water attraft the fixed air from the ve- Power of Quick-Lime. 
249 
These petrifying waters were formerly 
condemned, as being apt to create the 
done, but later experience has daewn, that 
the waters which abound mod; in this 
earthy matter, and which from the greated 
abundance of the cruds above-mentioned, 
are the mod; effectual diffolvents of the 
done, as is every day experienced with re- 
gard to the Carljbadt water in Bohemia. 
The abforbent quality of the faliva 
moreover fhews, how apt it mud be to lay 
hold of infectious miafmata, which often- 
times are in reality putrid vapours, or fixed 
getable fubftance, and the moment they are faturated 
they acquire folidity, become infoluble, and remain in 
the places of the vegetable particles, which are melted 
away. 
This change of a vegetable into a foflil fubftance, 
feems analogous to the change of iron into copper, 
which is brought about in no very long fpace of time, 
by leaving iron plates in a water that is ftrongly im- 
pregnated with a folution of copper in the vitriolic 
acid ; the fuperior attraction of the acid to iron caus- 
ing it to feize this metal, and let go the particles of 
copper. So, in the cafe of petrification, fixed air hav- 
ing a ftronger affinity with calcareous earth than it has 
with the vegetable fubftance, lets go the and 
feizeth on the former. On the Dissolvent 
air, detached from bodies during putrefac- 
tion; and confirms what hath been fre- 
quently recommended, namely, to fhake 
off infection *, and prevent the miafmata 
from getting into the mafs of fluids by im- 
mediate vomiting; and we may likewife 
fee, that the cautions given by authors con- 
cerning the fwallowing of tho, faliva, while 
in the places abounding wTith infectious va- 
pours are founded in reafon. 
It will not appear ftrange that fome of 
the animal fluids fliould contain fo little 
fixed air, when we find that the ferum of 
human blood feems almoft void of this 
element. 
EXPERIMENT 22. 
Having ordered fome ounces of hu- 
man blood, drawn from a healthy perfon, 
* By the precautions taken by Dr. Lindy and by im- 
mediate vomiting, “ only jive perfons died, from 
among more than an hundred, who were feverally, 
“ and fome of them conftantly employed, during eigh- 
‘•i teen months, in various offices about the fick, in 
<c Hafiar hofpital where there conftantly was a great 
number of people ill of fevers that were highly infec- 
tious. See his Dfcourje on Fevers and Infection, paper 
2d, p. 74. Power of Quick-Lime. 
251 
to be kept until the ferum and craffamentum 
had fairly parted, I mixed two drachms of 
the ferum with an ounce of lime-water: 
No change enfued; the mixture continued 
tranfparent, and, after forty-eight hours 
Handing, no precipitate could be per- 
ceived, while the liquor remained in the 
glafs ; but, upon pouring it out, a very 
fmall quantity of white earthy matter was 
found at the bottom, which, however, 
would not effervefce with vinegar. 
EXPERIMENT 23. 
About two drachms of the crajfamen- 
turn of the fame blood being put into a cup 
with an ounce of lime-water, and left for 
five days, did neither totally difiolve, nor 
turn putrid ; a piece of it being then taken 
out, and fpirit of vitriol poured on, an ef- 
fervefcence enfued, the lime which had 
penetrated, and joined itfelf to the fixed 
air of the craffamentum> now burfiing forth 
from every part of it, the moment the acid 
was applied. 
So that the fixed air appears to be con- 
nected chiefly with the red globules, and 
with that part of the blood called by Senac 252 
On the Dissolvent 
the lympha coagnlabilis; fince thefe two 
are found to compofe the crajj'amentum 
EXPERIMENT 24. 
Two ounces of lime-water being put 
into a tall drinking-glafs, about half an 
ounce of blood was allowed to flow from 
the vein of a perfon in health, into the 
glafs with the water: when it had flood 
fix hours, the mixture was all poured out, 
to about a drachm, which was differed to 
remain in the bottom of the glafs ; on this 
fediment fome fpirit of vitriol was dropped, 
and raifed a fmart ebullition, the calcare- 
ous matter turning white, as it boiled up 
on the addition of the acid ; fo that the 
fixed air, is eaflly detached from frefh 
blood. 
* There was a very ingenious thefis publiflied in 
1762, by Dr. Butt, when he took his degree at Edin- 
burgh ; which contains a number of very fatisfadtory 
experiments and obfervations, concerning the compo- 
nent parts of the human blood. The title is De San- 
guinis Spontanea Separation. Power of Quick-Lime. 
253 
EXPERIMENT 25. 
New bread: milk, when mixed with 
lime-water, in the proportion of one to 
three, in great meafure deftroyed the acrid 
tafle of the lime, yet did not caufe any fe- 
paration that was immediately perceivable; 
but after handing twelve hours, the pre- 
cipitation was vifible, and, on pouring out 
the mixture, the Tides of the glafs were 
found incrufted with a calcareous matter, 
which, as well as what fell to the bottom, 
effervefced violently on the addition of fpi- 
rit of vitriol. 
So that milk contains a large proportion 
of fixed air, and confequently ought not to 
be mixed with lime-water, fince it muft 
neceffarily take off from its activity. 
Dr. AIJion obferved very well, that 
there is fcarce any thing that is ufually 
mixed and given along with lime-water, 
that does net, more or lefs, deftroy its ef- 
ficacy ; for which reafon he recommended 
it always to be taken alone *. 
* Differtation on Quicklime, p. 41. fe£h n. 254 
On the Dissolvent 
Lime-water, when mixed with milk 
of any kind, prevents it from turning 
four; the reafon of which is obvious, 
becaufe, by abforbing and retaining the 
fixed air, the inteftine motion is prevent- 
ed, whence there can be no change of 
combination. 
I have now finifhed what was ori- 
ginally propofed; and, I hope, have fa- 
tisfa&orily fhewn, that fixed, air is the ce- 
menting principle, and immediate caufie, of 
perfiedl cohefion, at lead: in animal and ve- 
getable bodies * ; and though the experi- 
ments which I have made are very far 
from exhaufting the fubjeft, yet they cer- 
tainly are fufficient to raife curiolity, and 
to prompt men of leifure to a further in- 
veftigation of this important element ; 
* I have faid perfeSi cohefion, for, as Dr. Hales ob- 
ferves, “ Doubtlefs all the particles of matter what- 
“ ever do in actual contact cohere; yetfince it is found 
“ by experiment, that the moft folid parts of animals 
“ and vegetables yield a vaftly greater quantity of air, 
“ and lefs water, than the more lax and fluid parts, it 
“ feems therefore hence reafonable to conclude, that 
“ their folidity is principally owing, not to the watery, 
“but to the air and fulphureous particles.” Vol. ii. 
p. 280. 6 Power of Quick-Lime. 
255 
which ought not, by any means, to be 
confounded with the atmofpheric air: for, 
excepting its being for a time capable of 
elasticity, the fixed air does not appear to 
agree, in any other property, with the 
common air which we breathe. 
We know for certain, that the atmofifhe- 
ric air could not immediately penetrate the 
body of the lime-water, or other fluids, 
in the manner that the fixed air plainly ap- 
peared to do : This laft, though perfectly 
elaftic when firft fet free, yet, in a very 
little time, lofeth its fpring, mixeth with 
the liquid, penetrates every where, and 
rufheth into union with the difunited and 
fcattered particles of the fubftances dif- 
folved 
* The air which flies off from bodies, whether fo- 
lid or fluid, in the exhaufted receiver of an air-pump, 
is not the fixed air ; for this never departs but when the 
body to which it belongs either fufters a decompofition, 
or is diffolving into minute parts. 
Thus, if the mild volatile alcali, and the caufiic vola- 
tile alcali (viz. Sp. cornu ceryi per fe, and Sp. Sal. 
Ammon, cum calce viva), be both inclofed in the fame 
exhaufted receiver, the one will throw off as many air-  On the Dissolvent 
256 
But a ftill more ftriking diftinCion be- 
tween the fixed and the common atmofipheric 
air, may be remarked in the very different 
and oppofite effects which the two produce 
in the bodies of living animals. 
The fixed air, when fet free, and in 
a ftate of perfect elafticity, whether it 
be during the firft ftage of fermentation, 
by fire -j-, by effervefcence, or by pu- 
trefaction, if it be received into the 
lungs of any living animal, caufeth inftant 
death. 
But the fame elaftic matter, when re- 
ceived into the ftomach, whether thrown 
off from effervefcent mixtures, given in 
the way of medicine, or extricated from 
the food in the natural procefs of alimen- 
tary fermentation, is fo far from produc- 
ing any ill effeC, that, in the firft in- 
ftance, it often operates like a charm in re- 
ftraining vomitings, and, in the fecond, is 
bubbles as the other ; though we certainly know that 
the firft contains a large proportion of fixed air, while 
the fecond is entirely void of this principle. 
f Dr. Hales fuffocated a fparrow, by putting it into 
air that had been obtained by diftillation from heart of 
oak. Vol i. p. 176. Bower of Quick-Lime. 
abfolutely neceffary for the Support of life 
and health. 
With regard to the citmofpheric air, it 
is univerfally known that no animal can 
live long without frefh fupplies of it, and 
thofe who have lungs cannot exift many 
minutes without taking in large quanti- 
ties of this element. But if a very fmall 
portion of the fame be forced into the 
velfels of any living animal, death pre- 
fently enfues. * 
So that thefe two elements feem to be 
different in their natures, and to have 
quite ditUhdfc provinces with regard to ani- 
mal life : It is required of the firft, that it 
mix wholly with the blood; it feems fufii- 
cient that the fecond only communicate 
fome fubtile matter, or make fome imprefiio?i 
upon that fluid. 
It muff be confeffed, however, that 
notwithstanding what hath been juft now 
faid, we have not, as yet, a fufficient num- 
ber of facfts to determine pojitively, whe- 
ther thefe be originally difiinffi elements in 
nature ; or whether the fixed air is nothing 
more than a portion of the univerfial aerial 
fiuid, which is altered, and modified, from  On the Dissolvent 
its having been united with fome other 
principle 
It appears* however, from a circum- 
ftance peculiar to lime-water, that there 
is great ho re of the cementing principle al- 
ways floating in the atmofphere, which is 
ready to be abforbed by fuch bodies as 
have an affinity therewith ; for we fee that 
the particles of the diffolved quick-lime, 
which are neareft the furface of the water, 
* This Teems to have been the opinion of Dr. Hales, 
who looked on fixed air as a portion of common, re- 
pellent, elaftic air, deprived of its fpring, and reduced 
to a ftate of fixity and attraction, by the power of the 
fulphur in bodies. 
Dr. Cullen, if I atn rightly informed, teachetb, that 
phlogijlon is a compound, and holds fixed air to be one 
of its conftituents. 
Boerhaave was in fome doubt what to think concern- 
ing the fixed air. tc Dubitatum quandoque, an omne 
“ illud quod ita gigneretur foret quidem ejufdem ita 
<e naturae ut eodem nomine aeris elaftici appellari de- 
‘c bet ? an vero, corpora certa lege refoluta in partes 
t£ minimas, omifia natura fua prima, forte vera tranf- 
<c mutatione permutarentur in aerem hunc elafticum, 
“ quidein rurfum concretus aliis iterum firma redderet 
“ nova corpora ? an adeoque praeter aerem commu- 
<c nem elafticum, aliud illi fimile, non idem, in rerum 
te natura obtineret?” Element. Che?n. tom, i. p. 532. Lower of Quick-Lime. 
attrad the fixed air from the atmofphere, 
and form crufts, which are nothing more 
than the pure calcareous earth, fuch as 
the quick-lime was before calcination > and 
which, by the adion of fire, may be again 
reduced to quick-lime. 
And the abundance of fixed air in the 
atmofphere may be ftill further proved, by 
its deftroying the caufticity and folubility 
of quick-lime, and by its rendering mild, 
and effervefcent, the cauftic alcalies, when 
thcfe bodies are long expofed to the open 
air; and alfo by its adion on living vege- 
tables. 
It is univerfally known, that vegetables 
do not grow, or enjoy health, but in a 
free air; for as they are perpetually taking 
in fome nourifhing principle from the at- 
mofphere, they require that this ftiould 
be prefented to them in a continual fuc- 
ceflion. 
It feems pretty evident, that this is the 
cementing principle, as thefe bodies are 
found, upon analyfation, to contain a larger 
proportion thereof than can well be fup- 
pofed is fupplied by the roots, notwith- 
ftanding that there is found a good deal of 
fixed air in fome kinds of foil. 260 
On the Dissolvent 
The fixed air refides principally, if not 
altogether, in the moft elaborate part of 
t ie vegetable juice, the gum and the refin; 
and all bodies of the refinous kind, we 
have already feen, become foluble in wa- 
ter, when the cohefion of their particles is 
deftroyed by withdrawing the fixed air: 
but as this method of folution * may be 
applied to many ufeful purpofes in medi- 
cine, and perhaps in mechanics, it will not 
be amifs to lay down the feveral procefles 
with a greater degree of accuracy and pre- 
cifion. 
* Until within a few days before thefe papers were 
fent to the prefs, I looked on this method of diffolving 
refmous bodies as a difcovery, not having obferved, 
when I fir£t read Dr. Lewis's Materia Medica, that the 
diffolvent power of quick-lime, with refpeil to thefe 
fubftances, is known to that ingenious and ufeful wri- 
ter. The paffage relating to this matter is under the 
head of calx viva, and runs in the following words. 
“ Lime-water diffolves, by the afliftance of heat, 
“ mineral fulphur, vegetable oils and refins, and ani- 
mal fats; it ex trails in the cold the virtues of fun- 
“ drv refmous and oily vegetables, and diffolves thick 
ct phlegm, or mucous matters, and the curd of milk, 
“ with which laft it forms a white liquid, nearly fimi- 
i( lar to milk in its natural ftate.” Power of Quick-Lime. 
261 
It has been already mentioned, that 
the folutions made by the means of quick- 
lime, do all of them contain a certain pro- 
portion of the fame; but as this may fome- 
times be reckoned injurious to the virtue of 
the medicine, camphor, and the feveral re- 
finous bodies, may be diflolved in fuch 
manner as not to contain a fingle particle 
of quick-lime ; as for example, 
Take of camphor one drachm ; 
• double-refined fugar one drachm; 
fimple lime-water one pint; 
Rub the camphor and the fugar toge- 
ther into a fine powder, and then gradu- 
ally pour on the lime-water; let the whole 
Hand for two hours, and then pafs the li- 
quor through a filter. And thus will be 
produced, not indeed an intire folution, 
but a much Hronger one than that in the 
common julepum camphoratum. 
In the common way of making the 
julepum e mofcho fas directed in the London 
Difpenfatory) fcarce any of the mujk is dif- 
folved ; but if it be made in lime-water, a 
perfect folution of the finer and more ac- 
tive part of the medicine will immediately 
take place. 262 
On the Dissolvent 
Take of mufk one fcruple ; 
. double-refined fugar one drachm j 
lime-water fix ounces; 
Rub the mufk and the fugar together, 
then add the lime-water and filter, as be- 
fore dire&ed. 
To this, as well as to the foregoing, 
the prefcriber may add any fpirituous wa- 
ter, or the volatile alcaline fpirits, with- 
out deftroying the tranfparency of the fo- 
Iution. 
In like manner may fcammmy, or rejin 
of jalap, be diffolved ; and if fome grains 
of "Jamaica pepper be added, and rubbed 
up along with the fugar and other ingre- 
dients, it will communicate a mofl agree- 
able cinnamon flavour, that entirely covers 
the tafte of the jalap, or fcammonyf 
These folutions make very elegant and 
pleafant purging draughts j only it muff 
be remembered to order near triple the 
quantity of either the rejin or the fcammo- 
ny> that would anfwer if given in fub- 
flancej for the refinous particles are fo mi- 
nutely divided in this fort of folution, that 
they give but a very gentle degree of irri- 
tatipn to the bowels. Power of Quick-Lime, 
263 
If an acid fplrit be poured upon what is 
left on the filter, after any one of the 
foregoing folutions, it will be found to 
raife a fmart ebullition; which plainly 
fhews that the quick-lime that was dif- 
folved in the water is now faturated, and 
rendered folid, by the cementing principle, 
and has changed places with part of the 
refinous body, which remains diffolved in 
the water, while the lime is precipitated. 
But there are cafes wherein the lime 
will bid fair to improve the virtues of the 
refinous folutions; as, for infiance, when 
the cortex is prefcribed merely with a view 
to its aftri£tive quality, as in fcrophulous 
and relaxed habits, in order to check or 
dry up ulcers, gleets, or uterine difcharge; 
and here it may be ordered in the following 
manner: 
Take of Peruvian bark, in powder, two 
ounces; 
— quick-lime one ounce; 
lime-water thirty ounces; 
Rub the bark and the lime together, 
until they be thoroughly mixed ; then gra- 
dually pour on the lime-water; let the 
whole fiand for twelve hours, and then 
pafs the liquor through a filter.  On the Dissolvent 
264 
And thus will be obtained a mod ele- 
gant, and not unpalatable tindture, which 
may be taken, either quite alone, or in 
rny convenient vehicle, and in what quan- 
tity the prefcriber fhall judge proper. 
I can venture to allure the reader, from 
experience, that the bark, given in this 
manner, and in the cafes above-mentioned, 
produceth excellent effedts. And where a 
yet ftronger aftringent is required, oak- 
bark, managed in like manner, has been 
found to anfwer exceedingly well. 
Rhubarb, prepared in the fame man- 
ner, yields a beautiful tindture, which pro- 
mifeth to be of great fervice in all cafes 
where fmall quantities of this root are 
given with a view to ftrengthen the bow- 
els, and to preferve them free from a load 
of vifcid llime, as in weak and ricketty 
children. 
Aloes, when joined with the lime, is 
not near fo naufeous as when dilfolved in 
the common way ; and therefore indepen- 
dent of the lime, whofe virtues, as an an- 
thelminthic, are confiderable, bids fair to 
be of great ufe ; for children, who gene- 
rally are the patients in thefe cafes, will Power of Quick-Lime. 
265 
probably be induced to take the medicine 
better when thus made up, than when it 
is prepared in the ufual manner. 
Myrrh and faffron may be occafionally 
joined with aloes; and being all diffolved by 
the means of quick-lime, will make an 
efficacious elixir proprietatis, as the lime 
will certainly improve the virtues of the 
other ingredients, in mod: cafes where a 
compofition of this fort may be ordered to 
advantage. 
GuxM guaicum diffolves very com- 
pletely, in the manner we are now fpeak- 
ing of, being rubbed up with an equal 
quantity of quick-lime, and afterwards 
mixed with the requifite quantity of lime- 
water ; and perhaps may be found a more 
powerful medicine, in cold rheumatic 
complaints, than the common tindlures: 
I have not, indeed, made trial of it; but I 
find that cajlor anfwers exceedingly well, 
given in this manner, and may be taken in 
large dofes, without offending the flomach. 
Two drachms of cajlor, rubbed up with 
a drachm of quick-lime, and mixed with 
fix ounces of lime-water, give a ftrong and 
elegant tincture, which may be flavoured 266 
On the Dissolvent 
by adding nutmeg-water, or any other of 
the like fort, and then given in dofes of 
two or three fpoonfuls, as often as fhall be 
thought convenient. 
It will, no doubt, be reckoned fuper- 
fiuous, that lime-water is ordered to be 
added to thefe feveral fubdances, when 
they are alfo to be rubbed along with 
quick-lime j but the reafon is this: If the 
lime were fo quick and frefli as to raife 
heat when common water is poured on it, 
the folution might then be made without 
the aid of lime-water; but as it will, for 
the mod; part, happen that the lime kept 
in the {hops will not be perfedly freih, it 
will be bed: that the prefcriber lhould di- 
red: lime-water to be ufed, in order to be 
fecure of the folution, which would not be 
fo completely made, nor fo much of the re- 
dnous fubdance be didolved, if flacked 
lime and common water only were made ufe 
of. 
And it is much the fame thing in the 
end, with regard to the proportion of lime 
in the folution ; for although lime-water 
may receive fome additional drength, from 
being poured repeatedly on fredi quick- Power of Quick-Lime. 
267 
lime (as Dr Whytt and Dr. Home * infill, 
in oppofition to Dr. AlJiori)t yet here the 
quantity acquired muft be fo very inconfi- 
derable as not to be worthy of notice. 
* See Dr. Whytt's paper on this fubjeft, in the firft 
volume of the Edinburgh Phyfical and Literary Eflays, 
and Dr. Home's experiments on bleaching. In the laft- 
jnentioned book (which I had not read when I made 
my experiments), I have the pleafure to find many 
things perfectly coincide with, and confirm, as well 
the general theory laid down in the foregoing effays, as 
what relates particularly to the antifeptic power, and 
po the nature of petrifying waters. 
FINIS. ERRATA. 
Page line 
a 7 4 inftead of from read by, 
72 4 for arrive read arife, 
94 12 for nor read on. 
144 19 dele as. 
146 14 read (figure) 2 inftead of it, 
176 3 read in inftead of of. 
a 19 12 for yellowing read yellmvijb, 
256 to read putrefaBion, 
Page—Line 
94 12 for nor, read on. 
171 (in the note) for bhod's fibres, r, bhod and fibres* 
172 5 for ihefe, r. there. 
I74 20 for any, r. every. 
220 4 for latter, r. natural. 
223 9 for appearing, r. enabling the water. 
249 5 for frotn, T.form. 
Befide the following, which do not fo much affett the fenfe* 
Page 1, line 3, read tranfmutations. p. 160,1.8, r.perfpira- 
tion. p. 176, 1. 3, for of, r. in. p. 227, 1. 21, for drank, r. drunk, 
p.138, in the note, r. kinds, p.142, 1. 5, for ones, r. one. 
And in the firft figure, the engraver has committed a very 
great mi (take, by not reprinting the Cylindrical Gla/f C, as 
inverted.