AN
INAUGURAL DISSERTATION
ON
THE CHEMICAL AND MEDICAL HISTORY
OF
SEPTON, AZOTE, OR NITROGENE;
AND ITS COMBINATIONS WITH THE
MATTER OF HEAT AND THE PRINCIPLE
OF ACIDITY.
SUBMITTED TO THE PUBLIC EXAMINATION
OF THE
FACULTY OF PHYSIC,
UNDER THE AUTHORITY OF THE
TRUSTEES OF COLUMBIA COLLEGE
IN THE
STATE OF NEW-YORK:
WILLIAM SAMUEL JOHNSON, LL.D. President:
FOR THE DEGREE OF
DOCTOR OF PHYSIC.
ON THE THIRD DAY OF MAY, 1796.
By WINTHROP SALTONSTALL.
Citizen of the State of Connecticut.
" If the phenomena of animal bodies, as is highly probable, depend upon the
matter of which they are composed, and if their respective functions be the
result of a peculiar combination of matter; then must CHEMISTRY chiefly
pave the way for A RATIONAL PHYSIOLOGY OF ANIMAL BODIES, be-
cause it acquaints us with matter and its constituent parts."
REIL.
NEW-YORK:
Printed by T. and J. Swords, Printers to the Faculty of Physic of
Columbia College, No. 99 Pearl-street.
-1796.-




PREFACE.
PREVIOUS to commencing the chemical history
of the subject of these pages, I must apologize for the
assumption of the new term by which I have designated
it: this is the more necessary, as a diversity of terms,
expressive of the same idea, may be said to retard the
advancement of knowledge; and especially as the inno-
vation of an unexperienced student may have the appear-
ance of boldness or presumption: yet the reasonableness
and propriety of the thing itself, it is hoped, will amply
warrant the adoption. It is well known, that the com-
binations afforded by nitre have been hitherto considered
as of mineral origin, and that the terms azote, azotic,
nitrous, nitric, &c.* were adopted by the French Aca-
demicians ; and as the first of these and its derivatives
were exceptionable, the term nitrogene had been substi-
tuted for it by some of the later writers: † but, from
the evidence of the most striking facts, we shall, in the
sequel, be able to prove, that the nitrous acid, forming
a part of the salt nitre, is of animal derivation, formed
from azote and oxygene, during the putrefaction of
substances of that kind; and that by the addition of the
vegetable
* See Table of Chemical Nomenclature, by Lavoisier, &c. for 1787, title
Azote.
† Chaptal’s Chemistry, passim-Pearson's Translation of the Nomencla-
ture.


iv PREFACE.
vegetable alkali, and that only, is nitre formed. Hence,
then, we assume the word septon, to express the radical
of this compound, and derive it from σ η π ω, putrifacio,
whence comes SEPTON, putridum. Thus the combina-
tions formed from this base of the nitrous acid may
have new terms in the nomenclature, and be arranged
in the following order:-
Septon, for azote or nitrogene.
Septous gas, for azotic gas, or atmospherical mephitis.
Gaseous oxyd of septon, for dephlogisticated nitrous air.
Septic gas, for nitrous gas.
Septous acid, for nitrous acid.
Septic acid, for nitric acid.
Septate, septite, for nitrate, nitrite, &c.
I think it proper here to premise the liberal use I
have made of the published sentiments of my friend and
instructor, Professor MITCHILL ; the attendance on
whose valuable lectures, in the College of New-York,
has afforded me a large share of materials for the pre-
sent dissertation ; and who first suggested this alteration
of the nomenclature.
CONTENTS.


CONTENTS.
CHAPTER I.
The Chemical History of Septon, and its Combinations,
including,
Sect. 1. Septon and Septous Gas.
Sect. 2. Septous Oxyd, or Gaseous Oxyd of Septon.
Sect. 3. Septic Gas.
Sect. 4. Septous and Septic Acids.
Sect. 5. The Difference between the Gaseous Oxyd of Septon
and Atmospheric Air.
Sect. 6. The Identity of what has been termed Contagion and
Marsh-Miasmata.
Sect. 7. Observations and Facts, proving the Identity of Cause
in the Production of Fever, and certain other Dis-
eases.
Sect. 8. That the Cause of Contagion, and of many endemic
and epidemic Diseases, is some Chemical Combi-
nation of Septon with Oxygene.
Sect. 9. The Operation of the Causes of these endemic and epi-
demic Diseases on Vegetation.
CHAPTER II.
Its Physiological and Medical Operation-comprehending,
Sect. 1. The Operation of the Gaseous Oxyd and Septous Acid
Vapours on the Lungs, including Brute Animals
as well as Man.
Sect. 2. On the Alimentary Canal, or Stomach, and Intestines.
Sect.


vi CONTENTS.
Sect. 3. On the Cuticular Surface.
Sect. 4. On the Lymphatic and Glandular Systems.
Sect. 5. A new Theory of Fever.
APPENDIX.
Note A. Mitchill's Letter to Millar, on the Manner in which
the Materials of Dwelling-Houses are affected by
Septous Fumes and Combinations.
Note B. Martin's Letter on the Air of some Parts of Bengal.
Note C. Mitchill's Letter to Stevens, on the Manner in which
Septous Productions are affected by Water.
Note D. Mitchill's Letter to Livingston, on the Power of Ve-
getables to decompound and utterly destroy these
Septous Compounds; and on Nitrous Acid as a
Manure.
Note E. Bancroft's Application of the same Principle, to ex-
plain the Colours of Animal Substances in dying.
AN


AN
INAUGURAL DISSERTATION
ON
THE CHEMICAL AND MEDICAL HISTORY
OF
SEPTON, AZOTE, OR NITROGENE.
CHAPTER I.
The Chemical History of Septon, and its Combinations.
Section I.-Septon, and Septous Gas.
SEPTON is one of the most abundant elements in nature: com-
bined with caloric, it forms septous (azotic) gas, which com-
poses nearly two thirds of our atmosphere. No experiments hi-
therto instituted, have detected it in a distinct and separate form;
for its attraction for the matter of heat is so great, that in all tempe-
ratures of our earth it exists in the gaseous state. It is likewise one
of the constituent elements of animal bodies, in combination with
carbone, hydrogene, and phosphorus: these are united together by
a certain proportion of oxygene, forming animal oxydes and acids,
according to the degree of oxygenation. Oxygenous gas forms
nearly the other third of our atmosphere: occasionally, however,
other gaseous ingredients enter into the composition; but these are
to be considered as accidental, not essential to its constitution; and
an atmosphere in which there are other ingredients than oxyge-
nous and septous airs, may always be supposed to obtain, to a
considerable degree, in cities and other crouded places, and in
marshy and swampy situations.-Septous gas may be procured
from the atmosphere, by exposure of a given quantity, to be acted
upon by the sulphure of potash (hepar sulphuris), in a close ves-
sel, by which operation its oxygene is absorbed, and the septous
gas


( 8 )
gas left behind by itself. It is afforded by the decomposition of
the animal muscular fibre, both by an artificial and natural pro-
cess: in the former case by subjecting the muscular fibre to the
action of the septic (nitric) acid: during the process, the septous
gas is evolved; while the carbone and hydrogene of the muscle
run together, forming the oily pellicle floating on the surface.
That this process takes place in the natural and spontaneous de-
composition of the muscular parts of animals, under certain favour-
able circumstance, is evinced by the testimony of Mr. Sneyd,*
who gives an account of the conversion of a bird into a hard fatty
substance. It should seem to have undergone this change by long
submersion in the mud and sediment of a fish-pond. An analo-
gous instance, of the escape of this gas from its muscular union, is
inferred from the relation of a disorganizing process by Mr. Gibbs,
of Oxford,† in his paper on the conversion of animal muscle into
a substance much resembling spermacæti; and as also appears from
Fourcroi's report on the removing the Cimiterié des Innocens at
Paris. In all these cases the original structure of the parts ap-
peared to be the same, though their nature and properties were
very much changed by the process they had undergone.
This gas, in a pure form, is incapable, like oxygene air, of sus-
taining animal respiration ‡ and combustion: at the same time that
it and its compounds appear to serve as a pabulum vitæ of ve-
getables, whose œconomy is such as probably to decompound it,
and attach septon to themselves, as a nutritive ingredient.
Septous gas, combined with hydrogene gas, forms ammoniac
(volatile alkali); and it seems to be the opinion of the ablest che-
mist, that the other alkalies are like combinations. §
SECT. II.-Gaseous Oxyd of Septon.
SEPTON is capable of combining with the principle of acidity,
and the compounds, according to the degree of the oxygenating
process, are the following: 1. Gaseous oxyd of septon. 2. Septic
gas. 3. Septous acid. 4. Septic acid. All which are of a na-
ture so interesting as to merit a particular enumeration and dis-
cussion.
This combination of the principle of acidity, with septon and
caloric, in the first or lowest degrees, (for an acquaintance with
which we are indebted to the indefatigable labours of Priestley, by
whom
* Philosophical Transactions, for 1792, part ii.
† Repertory of Arts and Manufactures, No. viii. p. 105.
‡ Priestley’s Experiment and Observations on different kinds of Air, vol.
ii. p. 205.
§ Chaptal, vol. i. p. 108.


( 9 )
whom it was called dephlogisticated nitrous air) is possessed of
some surprising properties.
Previous to its discovery, from the analogy subsisting between
respiration and combustion, it was considered, that what would
facilitate the one, would have a like influence upon the other, and
vice versa, the same causes would impede both. But Doctor
Priestley informs us,* that this gaseous substance keeps up combus-
tion naturally and freely in a candle immersed in it; but is, at the
same time, highly noxious to animals, and destroys their life the
moment they are put into it. † " This surprising quality is doubt-
less owing to the difference in the attractive force which its oxy-
gene exerts for hydrogene in the one case (combustion,) and for
carbone in the other (respiration); for it is known, that by mixing
the gaseous oxyd of nitrogene with carbonated hydrogene gas, the
carbone is precipitated from its solution. Hence it appears, that
the attraction for charcoal is much weaker than for hydrogene, and
that although carbone may be made to burn in the gaseous oxyd,
hydrogene is the substance for which it has the closest affinity.
And we can now readily conceive how the hydrogene of the can-
dle may, in an especial manner, contribute, by attracting the prin-
ciple of acidity from the gaseous oxyd, to keep up the inflamma-
tion, wherein some part of the charcoal may likewise, though in
a secondary way, be converted to carbonic gas. It may be under-
stood too, wherefore it is not capable of sustaining life. There are
two important purposes answered by animal respiration; the one
to furnish oxygene to the phosphoric, sulphureous, and carbonic
matter of the blood; the other to carry off its surplusage of charcoal
by means of the lungs. Now, the gaseous oxyd has less action
upon phosphorus and sulphur, than it has upon charcoal. Hence
it is a very natural conclusion, that, in ordinary breathing, the ga-
seous oxyd does not only not yield its principle of acidity to the
blood in the pulmonic circulation, but at the same time does not
sufficiently attract carbone from the venous portion of it: whence
it comes to pass, that an animal inhaling an air, contributing to
neither of these salubrious processes, must speedily die; its blood
being both in a disoxygenated and super-carbonated state; hydro-
B gene
* Experiment and Observations on different kinds of Air, vol. ii. p. 55.
† Priestley seems not to have understood the composition of this air, and for
a considerable time it attracted but little notice from philosophers: yet, very
recently, Messrs. Deimann, Troostwick, &c. have prosecuted this subject with
much experimental accuracy, have confirmed the experiments of Priestley, re-
lated a variety of processes for obtaining it, and declared it to consist of 37
parts of oxygene, chemically united to 63 parts of septon.-Recherches Phy-
sico-Chemiques, &c. Amsterdam, 1794.


( 10 )
gene alone being the ingredient, in phlogistic operations, which
readily attracts its oxygene from the gaseous oxyd."*
During the plague at Marseilles, (which I shall hereafter endea-
vour to show was occasioned by the same vitiated state of the atmos-
phere that causes all pestilential and most epidemic diseases, to wit,
the chemical union of septon with oxygene) a great quantity of
wood, brush, and faggots were procured, laid in piles at small dis-
tances from each other, along the walls of the town, in all the public
walks, squares and markets, and at the house doors-set fire to at the
same time, and burned to ashes. This, though repeated till all the
fuel was spent, did no good. Afterwards, quantities of brimstone
were bought up and used in fumigations: but the sickness raged
with greater virulence than before.-The experiment made with tar,
in the city of New-York, in September, 1795, was of no service, and
the epidemic increased afterwards. The reason of which is obvious;
the gaseous oxyd resists the attractive powers of charcoal and sul-
phur, and cannot be resolved by them into its constituent parts.
Fires made with oil, fat, wax,  and tallow, might perhaps have been
advantageous, on account of the greater proportion of hydrogene
in these substances. During the plague in London, in 1665, large
fires of coal were continued, in many parts of the city, for three
days, and an unusual mortality immediately ensued. Was this,
it might be asked, by consuming the oxygene gas, while the oxyd
itself remained unaltered by the coal fires? If so, they are neither
useful nor harmless, but of the most pernicious consequence.
This gaseous oxyd can be separated from septous gas by its ready
miscibility with water, with which it combines, in its natural tem-
perature, in a very pure form, at the same time that it undergoes
no shrinking decomposition, or change, by mixture with the at-
mospheric fluid, nitrous gas, or vital air: but it is to be remember-
ed, that, by mixing with water, it is only taken out of circulation
in the atmosphere, and not decompounded; and on evaporation, or
the application of a sufficient degree of heat, it is dissevered from
its connection, and re-exists in the atmosphere.
This gaseous oxyd may be obtained by exposure of septic (ni-
trous) gas to the sulphure of potash (hepar sulphuris): after a
certain progress, in the combination of the oxygene and sulphure,
has been made, the residuum is found to have no acidity-to be
a proper oxyd, and to possess the permanently elastic properties
of a gas.
SECT.
* Mitchill on Contagion, p. 7 & seq.


( 11 )
SECT. III.-Septic Gas.
THE oxygenous principle, uniting with septon in a larger pro-
portion, forms septic (nitrous) gas: this being found to consist of
not less than 68 parts of oxygene, chemically united to 32 parts of
septon, and not unfrequently the acidifying ingredient being yet
several degrees more abundant.
From the avidity with which this fluid unites with oxygene, we
never shall be enabled to procure it from atmospheric air, but at
the instant of its disengagement from its original sources of deri-
vation ; for, on being let loose into the atmosphere, it instantly
unites with oxygene, after the manner it does in the Eudiometer,
and forms the septous (nitrous) acid. It differs further from oxy-
genous air, as it is incapacitated to support flame’s from hydrogene
gas, in being incombustible; from carbonic acid gas, in its smaller
specific gravity, its specific gravity being even less than atmosphe-
ric air,* whereas carbonic acid gas is greater.
" Plants die very soon, both in nitrous air, and also in common
air saturated with nitrous air, but especially the former. This
kind of air is as noxious as any whatever, a mouse dying the mo-
ment it is put into it: but frogs and snails (and probably other ani-
mals whose respiration is not frequent) will bear being exposed to
it, though they die at length. A frog, put into nitrous air, strug-
gled much for two or three minutes, and moved now and then for
a quarter of an hour; after which it was taken out, but did not re-
cover. There is something remarkable in the effect of nitrous air
on insects that are put into it. Wasps always died the moment they
were put into the nitrous air. I could never observe that they made
the least motion in it; nor could they be recovered to life afterwards.
This was also the case with spiders, flies, and butterflies : sometimes,
however, spiders would recover after being exposed about a minute
to this kind of air."
This gas may be obtained by submitting steel filings to the action
of the septous (nitrous) acid, by which operation part of the oxy-
gene of the acid, uniting with the iron, forms a septate or nitrate
of iron, and the other portion is evolved in the gaseous form. It is
this gas which, from its strong attraction for oxygene, is made use
of to ascertain the existence and  proportion of the later gas in che-
mical experiments: but from its great mutability, and diversity of
comparative strength, it is a precarious test; for, says the Abbe
Fontana, " the nitrous air which is made at one and the same time,
in the same flask, with the same nitrous acid, with the same iron,
and,
* Chaptal, vol. i. p. 288.
† Priestley's Experiment and Observations on different kinds of Air, vol. i.
p. 409.


( 12 )
and, what is more, the air which comes from the same flask, varies
extremely in its strength, and is more or less capable of diminish-
ing common air, and dephlogisticated (oxygene) air; or, to speak
more properly, being diminished by these airs, according to the
circumstances under which it is collected."*
SECT. IV.-Septous and Septic Acids.
THE next degree of combination, in which the acidifying prin-
ciple exists united with septon, is that of the septous (nitrous)
acid. Hitherto the origin of this acid has been deduced from the
mineral kingdom, especially from the salt called nitre, or the sep-
tate of potash. How far this deduction is founded in truth, and
how far it is warrantable, may appear from the following facts
cited, and inferences drawn, by the Professor of Chemistry, in his
late publication on the oxyd of septon. Speaking of nitre, it is
remarked, " that substance is known to consist of nitrous acid,
joined to potash. It is usually formed during the decay of animal
and vegetable bodies, and, by a spontaneous process, is produced
from their ruins. We are quite satisfied, that azote (septon) and
oxygene entered into the composition of those bodies when alive,
and have gone into new combinations on their disengagement by
death. One of these recent compounds must be nitrous acid, con-
stituting, by junction with a saline base, the nitrate (septate) of
potash. Thus the theory of the formation of salt-petre necessarily
presumes the generation of nitrous acid from two of the elements
disengaged from organic texture. And as azote, the radical of the
acid, is especially abundant in animal bodies, and, as Lavoisier †
says, favorise marveilleusement la putrifaction, wonderfully promotes
putrefaction, there is little difficulty in conceiving, both how, in
such circumstances, it attracts the acidifying principle, and after-
wards attaches itself to the alkali. But further than this, the autho-
rity of Mr. Becker‡ has been advanced in favour of the production
of nitrous acid without the aid of the putrifactive fermentation at
all. He found nitrous acid in the urine of cows, which had been
eight days exposed to the sun. He mixed some of the soakings of
a dung-hill with a ley of burnt sheep's dung and chalk in powder.
The mixture began to ferment on the following day, and on the
fourth, the internal commotion having ceased, he found, at the
bottom of the phial, regular chrystals of prismatic nitre. He
ascribes the nitrous acid, not to a process going on in the air, but
brought
* Recherches Physiques, p. 9.
† I Traite Elementaire de Chimie, 155.
‡ Notes to Bergman's Elective Attractions, p. 327.


( 13 )
brought about by the exertions of animals. On examining the earth
of stables and cow-houses, he found its lixivium to yield prismatic
nitre, while that of the dung would afford only small chrystals,
which required an addition of nitre in order to be reduced to a
prismatic form: and he declares he can attract salt-petre at pleasure,
in the course of three days, from the earth of stables and cow-
houses, by using, for saturation, well purified pot-ashes. In the
production of salt-petre, the putrified substance, if of the animal
kind, affords little more than the nitrous acid. This was known
to Boerhaave, who says, the nitrous quality of the earth is derived
from the excrements of animals and their putrified carcases, parti-
cularly such as do not use sea-salt, as birds, which, by the addition,
of the ashes procured from the burning of plants and of quick-
lime, forms salt-petre.* This fact, of the animal origin of the
nitrous acid, is confirmed by the testimony of Macquer, † who
declares, that in the putrifactive process which affords nitrous acid,
animal substances have a decided preference; so that, in order to
make a chrystalizable salt-petre from substances purely animal, a
quantity of the vegetable alkali must be added; whilst the salt-
petre produced in the putrefaction of vegetables alone is naturally
found to be furnished with that quantity of fixed alkali, which is
necessary to form good nitre." To this may be added the autho-
rity of Fourcroi.‡ When, to all this, it is subjoined, that on ana-
lizing the soil taken from the bottoms of graves, where human
bodies have putrified, it has been found, though having no com-
munication with the external air, to be highly charged with nitrous
acid, the animal origin of this acid is put entirely out of doubt.
Again,
In a treatise on salt-petre, by James Massey, Esq; § from the
learned and perspicuous manner in which the subject is treated,
we are enabled to deduce the most ample proofs of the animal
origin of this acid, independent of other sources of information.
" If we throw a fixed salt into any putrid liquor, it will be nutra-
lized by it: and now, if we dip a piece of soft paper into this mix-
ture, and dry it, it will burn like a match, in the same manner as
if dipped into a weak solution of salt-petre; which shows, that it
not only contains an acid, but one of the nitrous sort."-“ But the
strongest proofs of the existence of an acid in putrid juices, if the
earths of stables and cow-houses do not afford an equal one, must
be drawn from the soil at the bottoms of graves, which can cer-
tainly
* I Elementa Chemie, 44.
† 3 Dictionare de Chemie, 18.
‡ See 2 Lecon. Elementaires, &c, 842.
§ Repertory of Arts and Manufactures, vol. i. p. 248 & seq.


( 14 )
tainly derive its nitrous quality from nothing but the corrupt bo-
dies with which it lies in contact: and this may satisfy us in respect
to the source from which other absorbent earths may derive it."-
"The common soil, in some parts of India, is naturally nitrous,
owing plainly to the fish and slime that are left upon it by the inun-
dations of the river Ganges, which soon corrupt in that hot cli-
mate, and fill the earth with putrid juices; and here putrefaction,
being carried on with the greatest rapidity, is of course soon com-
pleted, and the natives are, in a short time, furnished with a nitrous
earth perfectly maturated. But it must not be forgotten, that their
strongest earths are found at the bottoms of their tanks, or shallow
ponds of water, which, in that country, are often of great extent,
and in which, the water being evaporated by the heat of the sun,
large quantities of fish are left to corrupt, which furnish a mud
of the strongest nitrous quality. In this manner nitrous earths are
naturally formed in those parts of the world."
A sensible English traveller * has given an account of the salt-
petre works in Grenada, and agrees with this idea of the formation
of nitrous acid by the combination of the base furnished by ani-
mal putrefaction with the vital air afforded by vegetables; observ-
ing, at  the same time, that animal substances simply, by putrefaction,
afford nitrous air also.
One of the most important facts, relative to this acid, is its occa-
sional existence in the atmosphere: in establishing which we shall
comprehend the several other modifications of it. And,
1. " Margraff, in the year 1751, † collected, in the suburbs of
Berlin, as much snow as, when melted, afforded him one hundred
measures of water, each measure containing 36 Ounces. He col-
lected the snow in an open situation, in clear glass vessels, after the
atmosphere was purified by its having snowed some time: in short,
he used every possible precaution to procure the snow free from
every extraneous impurity. The nitrous or other salts contained
in the snow, as it fell upon the ground, were no doubt dissolved in
the water after the snow was melted; and in order to ascertain their
quantity and quality, nothing more was requisite than to dissipate,
by evaporation or distillation, the water in which they were dissolv-
ed. From these hundred measures of snow-water, he obtained,
by distilling it with every suitable attention, 60 grains, not of nitre,
but of calcarious earth, together with some grains (he does not
mention the exact number) of the acid of sea-salt, impregnated
with nitrous vapour."
2. " The same quantity of rain-water, collected in the winter
months with equal precaution, and distilled with equal attention,
yielded
* Townsend’s Journey in Spain, vol. iii. p. 91.
† See Watson's Chemical Essays, vol. ii. p. 79, &c.


( 15 )
yielded 100 grains, not of nitre, but of calcarious earth, with some
grains of the acids of nitre and sea-salt."
3. The same chemist found some of this acid in the common
well-water of the city of Berlin; and Dr. Black, of Edinburgh, is
of the opinion, that it will be found to exist more or less in the
wells of all other great cities.*
4. It is satisfactory to the establishing the existence of this acid
in an aeriform state, to inquire whence the plastered lime-walls of
old buildings should acquire so much of this septous (nitrous) acid
for œconomical uses: and from considering the height of such
walls, and knowing the elective attraction which exists between
this acid and lime, we can scarcely divert the conclusion that it is
derived from the atmosphere of such habitations, and entering into
combination with the lime, forms the septate (nitrate) of lime. †
5. But were all these facts deemed inconclusive, we might ad-
duce the direct experiment of Mr. Thouvenel, who, a few years
since, obtained the prize, from the Parisian academy, for procuring
nitrous acid from atmospheric air and putrid vapour. ‡
6. It was related by the professor of chemistry, from a respect-
able authority, § that water which had been accidentally set aside
in an open vessel in the Island of St. Croix, after some time became
tinctured with nitrous acid, which the observer supposed to be
derived from the air. Here then should seem to be a spontaneous
process for its formation. And in the experiment for making
water by synthesis, Mr. Cavendish constantly found that the pre-
sence of azotic (septous) gas, when the oxygene and hydrogene airs
were burnt together, by the intervention of the electric spark, for-
med nitrous (septous) acid. ‖ Now, if the electric spark can affect
this artificially, may it not fairly be presumed that the same ope-
ration goes on upon a larger scale naturally in our atmosphere, by
the agency of lightning. Priestley also obtained an acid in the same
way, as appears from his experiment relative to the decomposition
of dephlogisticated and inflammable airs. ¶
The further combinations of this acid, with different bases, are
expressed in the Nomenclature of the French academicians, to
which a reference may be had ; for, considering the preceding mo-
difications as those only which will be of immediate import to our
future considerations, we shall avoid a further enumeration of
them ;
* Mitchill's Manuscript Notes from Dr. Black's Lectures.
† See Appendix, note A.
‡ See Bergman's Dissertation on Elective Attraction, note to page 96.
§ Mr. Van Rohr, a celebrated botanist.
‖ Chaptal, vol. i. p. 229.
¶ Page 67.


( 16 )
them; and after observing that the septic (nitric) acid differs from
the septous alone, in the superior degree of oxygenation; the sep-
tous, in its common form, being found by Lavoisier * to contain
nearly two parts of septon, less than two of oxygene, and about
thirteen of water ; † and the septic differing from it chiefly in being
more highly charged with oxygene; and that it has its respective
combinations in common with it; we pass onward to state, in a
more clear and satisfactory manner, the discrimination between
the septous oxyd and atmospheric air, to which a separate section
is reserved.
SECT. V.-The difference between the gaseous Oxyd of Septon, and at-
mospheric Air.
THEY both consist of like ingredients, but vary in their pro-
portions and combinations. The atmosphere is composed of 73
parts of septous gas, and 27 of oxygenous; but these are mixed
together mechanically, just as wheat and rye are distributed in a
heap of grain, or as sand and shells lie dispersed along the sea-shore.
The particles of each are fully mingled with those of the other;
but during all this intercourse, both septon and oxygene retain
their attraction for caloric in full force; and while this continues
to be the case, no union takes place between the putrifying and
acidifying principle, as, in common circumstances, both possess a
stronger attraction for the matter of heat than for each other.
The proportions of these ingredients, in our atmosphere, are not,
however, invariable; for sometimes the one, and sometimes the
other predominates, according as the one is absorbed or fixed, and
the other effused, or set loose in greater quantity in the operations
of nature. The proportions stated seem to be about the mean
ratio; and the reason of their not more frequently combining
and spoiling the respirability of the atmosphere, is, that when once
they assume the form of gas, they have less affinity to each other
than to the fire, which gives them their permanent elasticity :-
The requisite to their chemical union then is, the abstraction of
their colonic.
If there is any process in which the principle of acidity and of
putrefaction lose their quota of heat, and enter into combinations
with
* Chaptal, vol. i. p. 227.
† It must be remarked, that in all these compounds, in each of the forms and
varieties, a certain portion of water is in ordinary circumstances always present,
not as a necessary or constituent ingredient; but from the very strong attraction
between it and aeriform and liquid substances, it is almost impossible to deprive
them of it completely. Hence, in estimating the properties and effects of each
of them, it must be ever remembered, that water enters into the composition.


( 17 )
with other elements, to form organized or other bodies of complex
structure; in that case, the main impediment to their union, calo-
ric in excess, will be removed, and there will be a possibility of
their junction. It is admitted, that septon and oxygene enter into
the composition of certain animal and vegetable substances: but,
in the living state of these, they are connected with other elements,
in triple and quadruple alliances, and continue thus united until
their connection is severed by the disorganization of their fabric
after death.
There appears thus a situation, during the decay of organized
bodies, in which naked septon and oxygene may come within the
sphere of each other's attraction, without entering into an inter-
mediate state of gas, by union with caloric: and in this way, it is
probable, the nitrous acid is formed during putrefaction. The
process is as intelligible and easy to be conceived, as any instance
of chemical connection whatever. The case, at the same time,
is not by any means peculiar or unparalleled; for the union of car-
bone with oxygene, to form fixed air (carbonic acid  gas) in the
lungs, during respiration, and of hydrogene with oxygene, to
constitute water in the same function, is brought about in an ana-
logous way: and Professor Mitchill supposes it is in this way that
animal and vegetable secretions are effected, as there appears to be
some machinery in their œconomy whereby the ordinary impedi-
ments to chemical union are removed, and compounds afforded
thus that are producable in no other way. This he suspects to
be chiefly effected by depriving oxygene, hydrogene, and septon, of the
proportion of caloric necessary to convert them to gases;  and thus bring-
ing the uncombined elements into closer connection, with stronger
appetites to adhere to other substances and to one another; and so,
most probably, gum, mucus, bile, resin, pus, sugar, starch, &c.
are formed.
Hence it is apparent, that both during the life and after the
death of organized beings, compounds are made that are not imi-
table by any art, or to be produced any where else, or by any other
means, owing to the singularity of the circumstances in which the
component elements then and there exist. Among these animal
products, the septous (nitrous) acid, and the other combinations
of septon, with the principle of acidity, have not generally been
viewed in a proper point of light, either as respects their origin or
properties. The alkaline quality was always thought to character-
ize putrefaction; and the exhalations from corrupting animal sub-
stances have ever been deemed to be some modification of ammo-
niacal gas. The extrication of this species of gas, in common
cases, though it appears highly improbable, may, however, possi-
C bly


( 18 )
bly take place; but even upon the supposition that ammoniac
should be formed, yet the extrication of it, as will be shewn here-
after, would appear totally inadequate to the explanation of the
phænomena ascribed to it.
It is only said, in addition to this, there is another compound,
formed, at the same time, by the union of the principle of acidity
with the same radical, and that, according to the proportion in
which the former connects itself with the latter, will septous oxyd,
septic gas, septous acid, and septic acid, be produced. The viscera
and muscles of carnivorous and graminivorous animals contribute
eminently to the formation of these; while, in the livers of fishes,
and some other species of animal machinery, putrefaction disen-
gages septon by itself, which, joining with caloric, constitutes mere
septous (azotic) gas,* as another occasional result of this kind of
disorganization. According to the texture and composition of the
animal or vegetable material, will the result of putrefaction be;
the septon, in the simplest case, barely uniting with the matter of
heat into septous (azotic) gas-; or, in other instances, combining
with hydrogene into volatile alkali, or joining, under yet other cir-
cumstances, with oxygene, in varied proportions, to form the seve-
ral enumerated products.
It is stated, on the authority of the Dutch chemists, † that the
septous (azotic) oxyd consists of 63 parts of (septon) united with
37 parts of oxygene. The proportion of the principle of acidity
is greater in this chemical compound, than in the atmosphere, where
it is wholly disengaged and separate. How then, it has been asked,
can the base of vital air, the very principle of animation, become so ve-
ry deleterious as to excite distemper and destroy life, by merely
combining in a small over proportion with septon ? Just in the
same way, it may be replied, that, by combining in a somewhat
larger proportion, it constitutes, with the same radical, the more
caustic and destructive septous (nitrous) acid itself. There is no
reasoning a priori, from the known qualities of two substances, in
their distinct state, to what will be the qualities of the tertium quid
they compose by union. It may be inquired, if these two ele-
ments are so prone to unite after death, why, as they are in constant
neighbourhood in the animal solid, they do not associate during
life? It is probable in certain morbid cases they do; and cancer,
and some other eroding and incurable ulcers of the lungs, face,
neck,
* Mitchill found by experiment, in the autumn of 1795, that the fluid dis-
tending the abdomen of a swine putrifying after being strangled, was a mixture
of septous (azotic or phlogisticated) and carbonic acid (fixed) airs.
† Deiman, Troostwick, &c.


( 19 )
neck, uterus, &c. have been suggested as examples of its causticity
when thus produced.
Notwithstanding there are but four stages of combination discri-
minated betwixt septon and oxygene, yet it is not unlikely, that
between each there are intermediate degrees of connection; that,
for instance, a given compound, divided into 100 parts, may have
99 of septon and 1 of oxygene, or 98 of septon and 2 of oxygene,
and so on, or vice versa, in all the possible varieties of combina-
tion. This enlarged idea of the subject will go a great way toward
the explanation of the degrees of poisonous activity in different cases
of contagion; the materials of which, though always of the same
kind, may vary in their proportions, and impart to that mischievous
fluid more or less virulence and activity.
According to this doctrine, septous acid ought to be capable of
resolution into atmospheric air. In the explosion of gun-powder
this almost happens, for during the inflammation the salt-petre is
decompounded; and, while the septon of its acid is set loose, the
oxygene joins the charcoal to form fixed air. It is not impossible
that in some instances of imperfect explosion, the septous oxyd
may be formed in this way.
When putrifying substances in cities and marshes exhale this
dangerous fluid, there is commonly a considerable degree of heat
prevalent. In the city of New-York, the common range has been
stated to be between 75 and 85 degrees of Farenheit's scale; but
these fluids may be, and often are, emitted in cooler temperatures;
and  where the decaying materials are moist and plentiful enough,
the gaseous oxyd may continue to rise in the highest temperatures
we experience in our latitude of 40 deg. 40 min. What has been
thus stated, is therefore to be considered as only the ordinary range
in common seasons, wherein this species of air is produced from
the remains of dead bodies exposed to the vicissitudes of the weather.
As to its production within doors, an opinion is entertained that
the human body, whose temperature is nearly the same in every
season, may produce it during the coldest part of winter; and in
ships, prisons, and in some tenements of large cities, the process
seems to be constantly going on. The air so formed does not seem,
however, to gain its utmost activity until the arrival of hot weather,
no degree of cold we are yet acquainted with being capable of fixing it,
tho' ice very effectually stops its further formation from external sources.
Hence it is hoped the difference between the contagious fluid and
atmospheric air will be apparent; the one being a chemical con-
nection, whereby both the ingredients lose their separate qualities;
while the other is a mere distribution, or dispersion of the particles of
each among those of the other, possessing still their discriminating qua-
lities,


( 20 )
lities, and totally free from any combination with each other : the
former brought about by reason of the near approximation or
stronger attraction of the ingredients in the decaying body, before
they combine with coloric enough to turn them to gases; while in
the latter, such is the cohesive power by which septon and oxygene,
when once, as gases, united to caloric, stick to it, that the weaker
attraction they have for each other cannot in ordinary circum-
stances overcome it; and thus, in the same temperature, the ele-
ments may form septous oxyd or not, according to their respective
relations to other elements at the time, and the strength of alliance
by which they are bound to them. If the quantity of oxygene Is
greater in the oxyd than in the atmosphere, it is not more surpri-
sing than in the example of arsenic, quicksilver, antimony, sul-
phur, phosphorus, and charcoal, acquiring great change of quali-
ties, and becoming vastly more active by being charged with a
sufficient dose of oxygene; for, like several of the enumerated sub-
stances, septon is both an oxydable and acidifyable base. That such
a precise proportion of the base of vital air should be necessary to
convert septon into an active poison, is not hard to comprehend,
since, without it, septon is little better than a poison; it possesses no
salubrious properties, and, at best, deserves but the negative cha-
racter of not being mischievous.
What has been now offered is sufficient to shew the nature and
theory of these septous and septic compounds, and to make it ap-
pear that the salubrity of the  atmosphere, whose component parts
are commonly disjoined or distinct, is spoiled immediately on their
forming a junction, or becoming chemically combined.
This conclusion is confirmed by the following observations of
Dr. Beddoes:* “The nice balance of attraction between the two
constituent parts of the atmosphere deserves notice. These two
substances, when closely united, form nitrous acid. If, therefore,
they were not by some circumstances, prevented from uniting
closely, all the oxygene, with part of the azote, would be changed
into a highly concentrated acid, and the waters of our globe would
be converted into aquafortis," (septous acid).
And this is a perfect fulfilment of what Fontana † conjectured
long ago: " Thus then the respirable and wholesome air of the
atmosphere is composed of nitrous acid alone: but it is united with
more or less phlogiston, which varies the quality of it, not only in
proportion to its quantity, but also in proportion to its combina-
tion ; because, after all, phlogiston itself is a compound of several
principles,
* Considerations on the medicinal use and on the production of Factitious
Airs, p. 18.
† Recherches Physiques, p. 165.


( 21 )
principles, presenting itself to us under a thousand different as-
pects, and which, combined variously with other substances, forms
all the factitious airs with which we are acquainted.
" If the nitrous acid is convertable into air, and if the atmos-
phere is composed of this acid, decomposed, and deprived of its na-
tural phlogiston, it might happen, in this view of the subject, that
common air, in undergoing decomposition, should change to the
nitrous acid, and might even form salt-petre itself: it is certain
that nitre cannot be produced but in open air, that it is not formed
but in places where phlogiston abounds, and that it is a salt highly
charged with phlogiston."
SECT. VI.-The Identity of what has been termed Contagion, and
Marsh Miasmata.
IT is known that onions, plants of the tetradynamous class, the
paste  or  glutinous part of bread, &c. afford some results upon a-
nalysis greatly resembling those which animal substances yield.
When natural productions of these sorts go into spontaneous decay,
it may be expected they will yield aeriform products, nearly allied
to the animal class, if not quite the like. Maize and rice, consist-
ing almost wholly of amylaceous matter, emit very little or no
azote, and ought therefore to be most wholesome articles of diet.
The flour afforded by wheat, rye, and buck-wheat, contains a pret-
ty large proportion of glutinous matter, abounding with azote, and
should, on that account, be more prone to excite uneasiness in the
stomach and bowels, by running, in certain cases, into a putrifac-
tive state. Cabbage, onions, mushrooms, &c. should also, when
taken as food, be followed by much the same consequences as
meats. It is very difficult to draw the discriminating line between
animal and vegetable nature; and it is uncertain whether the ani-
mal resemblances may not extend much farther than the Fungi,
Gramina, and Tetradynamia. So far as plants or their parts ap-
proach in their nature and composition to animals, will they be
capable of resolution into similar products. The difficulty started
concerning vegetable putrefaction, as affording results essentially
varying from animal, is so far explained away, and reconciled to
fact.
The favourers of this distinction, it should seem, then, have
adopted their opinion too hastily; having never ascertained that
what they call marsh miasmata were the result of pure and unmix-
ed vegetable putrefaction. In declaring that it was so, they have
set up an hypothesis, and assumed a principle without proof, or
even probability to support it. I shall take, as instances of coun-
tries


( 22 )
tries exposed to these vegetable miasmata, Bengal, on both sides of
the Ganges, Louisiana, overflowed by the Missisippi, and Egypt,
covered annually by the Nile. These tracts of country, after the
evaporation, or withdrawing of a considerable part of the waters,
are found to have an unhealthy air. This unwholesomeness is not
imagined to proceed from any alteration in the existing atmospheric
ingredients: nor in that natural distillation called evaporation, is it
imagined that the atmosphere elevates, by chemical attraction, any
thing but pure water. As long as this continues to be the case,
there is no uncommon complaint of sickness. But by and by
the mud begins to be bare, and the air grows pestilential. Hence
it is said, proceeds the marsh miasma, from the mud and slime.
Let us then inquire what this mud or deposition from the water
is. Is it clear vegetable matter?-It is known to naturalists, that
the species of large animals are comparatively few. It is like-
wise known, that their numbers are comparatively small. Nor is
it less evident creation teems more particularly with animal exist-
ence in the warmer latitudes. The myriads of wild bees, locusts,
ants, cockroaches, sand-flies, musquitoes, which travellers have no-
ticed, and hundreds of other insect species, of which they knew nei-
ther history nor name, must, by their annual deaths, make an in-
calculable mass of animal putrefaction. The frogs, newts, lizards,
alligators, and other amphibious creatures, which yearly expire,
add greatly to the heap. The different verminous kinds, inha-
bitants of water and mud, contribute mightily to the sum. And
to all this must be added the vast amount of fishes which die natu-
ral deaths, or are left to perish or rot upon the shores. The re-
mains of all these animal productions are mingled with the waters
of these large rivers, as they wash and cleanse the countries they
pass through, from their sources in the mountains to their disem-
boguement in the ocean ; and yet, while such is the history of the
mud left by the receding rivers, and such the reason of its extra-
ordinary fertility, the effluvia arising from it has been considered
as something different from animal exhalation.
The case of stagnating water in ponds and swamps is precisely
similar, abounding in animal productions, which undergo putre-
faction during the evaporation of the water; and the greater heat the
surface of the mud acquires, when that process begins to abate.
The same thing occurs sometimes during the long calms ships
endure off the western coast of Africa, where the relicts of animals,
which float within a few fathoms of the surface, now rise to the
top, and form a putrid scum on the ocean water.
It is, indeed, questionable, whether there exists in nature an in-
stance of any thing like unmixed vegetable putrefaction, upon a
very


( 23 )
very extensive scale. Bogs of turf and of peat-moss come nearest
to it; and the water issuing from thence is very palatable and whole-
some. The formation of soil or mould in forests, is an analagous
process, but not of itself particularly noxious; for wherever much
morbid exhalation arises from it, there is ever an admixture of ani-
mal matter; and to this quickening of the putrefaction of ma-
nures does newly cleared land owe its abundant fruitfulness.
SECT. VII.-Observations and Facts, proving the Identity of Cause,
in the production of Fever and certain other Diseases.
CULLEN differed in opinion from Sydenham, and thought it
probable that in each of the species of disease enumerated in his
Nosology, the contagion was of one specific nature.*  He thought
it probable that contagions were not of great variety, since they
seemed to proceed much from one common source. As to mias-
mata, we know, says he, " only one species of it, which can be
considered as the cause of fever, and from the universality of this
it may be doubted if there be any other." He conceived it did not
differ in kind, but varied only in the degree of its power, or per-
haps as to its quantity in a given space. † Neither contagion nor
miasmata were, as he imagined, of great variety. ‡ And both arise
from putrescent matter. § The changing of the type of fevers, by
tertians and quartans becoming quotidians; quotidians turning to
remittents, and remittents altering to those of the most continued
kind, appeared to Cullen to evince, not only that every fever con-
sisted of repeated paroxysms, differing from others chiefly in the
circumstances and repetition of the paroxysms; but that it was fair
and proper to take a fit of pure intermittent as an example and
model of the whole. ‖
Balfour, in a treatise on putrid intestinal remitting fevers, compre-
hends the fevers called nervous, contagious, low, putrid, and ma-
lignant, together with many febrile complaints in the East-Indies,
which appear with peculiar local affections. He ascribes this class
of ailments to a putrified state of the mucus lining the intestines,
which being absorbed into the blood, causes the febrile state.
This mucus (he thinks) receives the infection first by means of conta-
gious matter taken into the stomach with the saliva. ¶
Wade** considers fevers and dysenteries to be ailments of a
kindred nature, and prevented and cured in the same way. He
considers fevers universally to arise in those latitudes, from the
bowels
* Practice of Physic, Sect. 79. † Sect. 84. ‡ Sect. 85. § Sect. 86.
‖ Sect. 32. ¶ Monthly Review for July, 1794, p. 336.
** Diseases of the East-Indies, page 130.


( 24 )
bowels and the matters contained in them; and are to be cured of
course by evacuations. He also thinks puerperal fever may al-
ways be prevented by effectual evacuations, from the bowels after
delivery.
Chisholm, in his observations on the malignant pestilential fe-
ver which raged at Grenada, in the West-Indies, remarks : “ Al-
though the contagion seemed to vary much in different descrip-
tions of people, it is highly probable that the virus of the conta-
gion itself was uniformly the same, only variously modified by
particular constitutions, habits, or mode of living, &c."
Writers have made a distinction between intermitting and re-
mitting fevers. This may be of use in medical description and
conversation; but from intermittents varying their types, and af-
ter a while becoming remittents, and then assuming the continued
form, and vice versa, it is argued fairly that they all spring from
one common cause.
Fordyce* declares, that he knows from his own observation,
which is corroborated by the authority of others, that intermitting
fevers are infectious ; and this is another trait of resemblance between
the two forms of fever. And Jackson † observed the changes from
intermitting fever to dysentery, and from dysentery to intermitting
fever, on this continent, so frequent in August and September, that
he had no doubt of their dependence on the same general cause.
The disease described by Zimmerman, ‡ as occurring in Switzer-
land in 1765, shews the connection between putrid fever and dy-
sentery. The analogy between the two diseases is very striking,
and appears to indicate respiration, injured by a bad state of the
atmosphere, combined with local affection of the alimentary ca-
nal. When the bowels were easy, the pulmonic organs alone were
affected ; the disease seems to have been what he calls the putrid
pleurisy of Lousanne.
And if it has been explained, how the difficulty of animal con-
tagion and vegetable miasmata can be got over and entirely recon-
ciled, then one general cause will be acknowledged to prevail;. and
according to the proportion of the ingredients entering into the
contagious combination; according to the sparse or concentrated
state in which the product is applied; according to the part or
parts of the human frame to which the application is made; or, ac-
cording to the readiness or slowness with which they take upon
themselves morbid action, and according to the co-operation and
concurrence of other circumstances, will the effect brought on by
the
* Dissertation on Simple fever, p. 111.
† Fevers of Jamaica, p. 331.
‡ Treatise on the Dysentery, chap. 1-2


( 25 )
the agency of this cause be. So that the recurring to a multiplicity
of contagions appears both unnecessary and unphilosophical.
Thus says Merli, in his description of the contagious epidemic
fever at Naples, in 1764: " This mischief, contagion, or poison,
or by whatever name you are pleased to call it, products in some
a malignant continued fever; in others a malignant double tertian, or
a malignant bloody flux. It sometimes attacks the head, at thers
seats itself in the breast, in the kidneys, or in some of the bowels,
and wherever seated, produces the most violent and malignant
symptoms."
" The disorders," says an intelligent writer,* " that prove fatal
to soldiers and Europeans in general in the West-Indies, are of
two kinds, namely fevers and fluxes. They are the concomitants
of armies in all parts of the world; but in tropical climates they
rage with peculiar violence. There appears to be an intimate con-
nection between them, for they are frequently combined together, often
interchange with each other, and it rarely happens that one is epidemic
without the other." He also affirms, † that " there appears to be an
intimate connection between the intermittent and remitting fevers of
Jamaica: the intermittent often running into the remittent, and
the remittent sometimes terminating in an intermittent." He de-
clares further, ‡ that " there subsists an intimate connection be-
tween remitting fever and dysentery; the one frequently chang-
ing into the other, and the two often complicated with various de-
grees of violence. In some cases the dysentery ends in a fever,
though much oftener the fever terminates in a dysentery, especial-
ly among the soldiers."
" From one cause, from the same infection," says Lind, § “ I
have frequently known to proceed what may be termed, from out-
ward appearances, the yellow patechial and miliary fevers; and while,
in a few, the contagion assumed an intermitting form, and was
mild, in others it raged with a constant and violent fever."
" The influence of jail-infection ‖ is much more extensive than
is generally supposed. Of a similar nature is the disease we fre-
quently read of in the public news-papers, under the names of
the scarlet, purple, and spotted fevers, which often depopulates cities,
and sometimes even whole countries.''
Cleghorn ¶ informs us that there seems to be a near alliance
amongst all the succeeding diseases prevailing at Minorca. " Those
who have the rash or Essere to a great degree, are very liable to
tertian fevers: on the other hand, in the paroxysms of tertians,
these cutaneous eruptions are apt to break out. The cholera mor-
D bus
* Hunter's Observations on the Diseases of the Army in Jamaica.
† P. 14. ‡ P. 218. § Essay on Seamen, p. 265. ‖ Ibid, p. 323. ¶  Dis-
eases of Minorca, ch. ii.


( 26 )
bus sometimes hath its regular periods like a tertian, as the parox-
ysms of tertians are frequently attended with a cholera. Some-
times a tertian turns into a dysentery, or a dysentery becomes a ter-
tian ; and when one of these diseases is suppressed, the other often
ensues: nor is it uncommon for dysenteric fevers even to put on the form
of tertians, and for the fits of tertians to be regularly accompanied
by gripes and stools."
That the diseases produced by contagion and miasmata originate
from the same cause, is countenanced also by Gardiner,* who co-
incides with the physicians of observation and experience, that
marsh miasmata can acquire a power as noxious as human con-
tagion ; and when it does so, the distempers caused by it are nearly
the same. Sir John Pringle was of this opinion, and so was
Count Carburi. And what is more to the point, Dr. Mackenzie,
who had resided along time at Smyrna, and a longer at Constanti-
nople, declares the common epidemic pestilential fever there, is
the same with the goal or hospital fever of England; and when
this same distemper grows more virulent, with buboes and carbun-
cles, they call it plague.
Cleghorn † further asserts: "These tertian fevers have as good
a right to be called contagious, as the measles, small-pox, or any other
disease; for although in that season there certainly is a peculiar
disposition in the air to affect numbers in the same way, yet those
who are much conversant among the sick, are most liable to catch
the distemper."
SECT. VIII.-That the Cause of Contagion, and of many endemic and
epidemic Diseases is some Chemical Combination of Septon with
Oxygene.
THE effluvia from putrifying substances, which constitutes con-
tagion, is neither hydrogene gas, nor any combination of it with
sulphur, charcoal, or phosphorus. These compounds are very
volatile and diffusable, and form a large part of the disagreeable
odour, or abominable stench of decaying bodies. The stinking
smell of substances is quite a different thing from infection. Nor
can carbonic acid air be the contagious material, though that ex-
hales abundantly from some sources of corruption. It has been
imagined, that ammoniacal gas was the injurious production, either
by itself, or in combination with something else; but the sensible
qualities of this, although it supports flame, and is miscible with
water, serve sufficiently to characterize it, and shew it is not the
deleterious cause in question. Besides its miscibility with water,
and
* See Animal Economy, p. 187. † Diseases of Minorca, note to p. 132.


( 27 )
and capability to maintain flame, though very faintly, alkaline gas
possesses enough of peculiar qualities to distinguish it from every
other animal production. We shall mention two of them:
1. When ammoniacal gas is mixed with water, it imparts to it a
strong alkaline tincture; insomuch that a water may be prepared
in this way, having a stronger alkaline smell than any spirit of sal
ammoniac at all. 2. Whenever alkaline air meets with carbonic
acid gas, a combination of the two fluids takes place immediately,
even in their aerial form, and concrete into oblong and slender chrys-
tals, which cross each other, and cover the sides of the vessel in
which the experiment is made, in the form of a net-work ; the
chrystals being of the same kind of volatile salt, obtained in a solid
form, by the distillation of sal ammoniac with fixed alkaline salts.
Hence, if ammoniacal gas is ever extricated during putrefaction, it
would instantly discover itself by imparting an alkaline flavour to
water; or, by combining with the fixed air, evolved at the same
time, will combine into firm chrystals of volatile alkali. This,
therefore, cannot constitute the matter of contagion. This conta-
gious cause we suppose to be sought for in the combinations of septon with
the acidifying principle, and to manifest itself in the septous oxyd, and
the vapours of the nitric acid itself: and in this view of the matter
can we account for the production of contagious diseases in dif-
ferent parts of the world, wherever the causes favouring the pro-
duction of these compounds exist.
Upon this idea, the occurrence of the epidemic in this city last
summer, may admit of a satisfactory solution; from the exist-
ence of the collections of vegetable and animal substances in the
different divisions of the city, and in a particular manner, in that
part of it where the malady raged with peculiar violence; since, on
examination, it has been found, that there existed in that neigh-
bourhood large heaps of manure, collected by the scavengers from
the streets and avenues of the city, and which were in that situa-
tion, undergoing the necessary disorganization, for agricultural
purposes. Now it has been pretty fully stated, that under such
circumstances, those septous compounds, which are the immediate
causes of contagious and infectious ailments, are uniformly extri-
cated by the application of heat and moisture; and when once so
formed, their influence on the neighbouring inhabitants is easy of
conception.
An analogous influence from the marsh effluvia arising from the
borders of the Onondago lake, is related by Vandervoort.*
" The marsh effluvia in this western territory, in many places,
and particularly in this place, operates so powerfully on the human
body,
* Analysis of Balston mineral spring water, p. 17.


( 23 )
body, as to induce a paroxysm of an intermittent, in the course of
four or five hours, and frequently death the seventh day.
" From ocular observations in these marshes, it appears, that
the poisonous effluvia is generated from the putrefaction of vege-
table matter, which, in its resolution, undergoes certain changes,
which produce this noxious air. It is also evident that this air
does not operate while the marshes are inundated."
Moores* informs us, that in  the state of Maryland, where the
marshy grounds are more extensively prevalent, remitting and in-
termitting fevers prevail ; and both diseases he ascribes to the same
cause, differing in degree. "Hoc vero ex observatione propria
edidici nempe cum in Marilandia, aestivus et autumnalis calor
minor quam solitus sit, tum populi in locis paludibus vicinis de-
gentes febribus intermittentibus tantum obnoxii sunt quando autem
aestatis et autumni calor intensior aestuet tunc febres remittentes
his ipsis locis epidemicæ grassantur.
“ In regionibus Marilandæ calidioribus qualis Carolina est, pa-
ludes solis radiis ferme excoquuntur, ibique febres remittentes
quam in Marilandia multo gravioribus symptomatibus stipantur
et proprius ad typhum icterodem accedunt. Monstrant hæc exem-
pla quantum febres cum ejusdem turn diversarum regionum se-
cundum tempestatis calorem varient. Hæ autem varietates mo-
do indirecte a calore pendent quippe paludum miasma pro causa
omnes agnoscunt et secundum vim ejus febres remittentes vel in-
termittentes sæviant; vis vero miasmatis ad tempestatis calorem
semper quadrat."
Dr. Valentin, who formerly resided in Cape-François, in the
capacity of physician to the camps and armies of St. Domingo, and
who was in Norfolk, in Virginia, during the sickness of 1795, in
a letter to Professor Mitchill, has the following comparative re-
mark on the diseases of the two places: " They offer the like train
and concomitancy of symptoms; I have here followed the same
method as there, with an equal success, when I was called in sea-
son. I do not contest about the word yellow-fever; that I consi-
der but as an effect, or a symptom, for it is not a new malady."
He adds also, his entire conviction of its local origin in Norfolk
and other sea-ports of the United States.
The contagious fluid, emitted from living bodies, is most plen-
tifully conveyed in the breath, perspiration, and stools. It has
been said to have a peculiar smell, and capable of being distin-
guished from all other known odours. They who have had in-
fectious air fresh in their nostrils, have called it an earthy disa-
greeable smell, affecting, in some degree, the organ of taste, and
extending
* Tract. Inaugural. de Febre Rmit. Marilandica.


( 29 )
extending down into the stomach: some have compared it to the
vapours issuing from a newly opened grave, but without the ca-
daverous stench ; others think it resembles the effluvia, of rotten
straw, and others again are of opinion it is like the exhalations
from confluent small-pox, at the turn of the pustules.
From the circumstances in which it is emitted, it is presumable
it is seldom admitted to the organ of smell in its pure form; but is
generally accompanied with some other gaseous emanation floating
about with it. Perhaps it is impossible to obtain it in a pure form,
but by an artificial process, and this may be the reason of the di-
versity of opinions concerning the odour ascribed to it, which is
probably not so much occasioned by the contagious fluid itself, as
by the other matters that are frequently extricated at the same time
with it. After diffusion through the air to some distance, it seems
incapable of exciting any sensation at all in the organ of smell.
From this inodorous quality of it, added to its capacity to support
flame, may some idea be formed why it has hitherto eluded the
search of inquirers.
The facts related by Mr. Martin,* and by Mr. Townsend,
concerning the vapours rising from the salt-petre soils of Bengal
and Spain, and their power of producing fevers, apply with great
force here. They are nitrous earths, naturally formed. The filth
collected in the streets of large cities, is a nitrous soil also. The
effluvia from the salt-petre soils of cities produces effects very si-
milar to those observed in the neighbourhood of natural nitre-beds.
This is verified most strikingly, as before remarked, in the dis-
ease endemic in New-York in 1795. The inference is, that the
septic (nitric) vapours, according to Thouvenel's conclusion,
are, in both cases, the cause of the consequent diseases.
SECT. IX.-The Operation of the Causes of these endemic and epide-
mic Diseases on Vegetation.
THIS is a subject of the greatest importance, as it involves a
material article of the police of crowded cities: for should it appear
that the vegetable economy was capacitated to disarm these com-
pounds of their baneful properties, the joint co-operation of con-
venience and usefulness would stimulate the officers of govern-
ment of these places, to disseminate vegetable life with as much
zeal, as the prejudice of ignorance has supported the measure of
exterminating it from the streets and public walks of the citizens.
No direct experiments, however, have yet been made on this
subject; but from the phænomena of the mitigation of the Samiel
and
* See Appendix, note B.


( 30 )
and Harmattan blasts in Africa, on their passing over tracts of
country cloathed with vegetable verdure, it is highly probable
they have an essential influence in altering or decomposing the
elements of such pestilential fluids.*
CHAPTER II.
Its Physiological and Medical Operation.
HAVING, as we hope, ascertained the cause of most endemic
and epidemic diseases, and the sources of their formation in
the various ways we have considered them ; we come now more
immediately to the application of these causes on our bodies; and
in this view of the subject we shall consider the operation of them,
on different parts of the body, in separate sections.
SECT. I.-The Operation of the Gaseous Oxyd, and Septous Acid
Vapours on the Lungs, including Brute Animals as well as Man.
THE operation of these causes on the lungs is accompanied,
according to their degree of continuance, with the following
symptoms:-Hoarseness, cough, catarrh, excretion of mucus
from the larynx or bronchia, lassitude, languor, shivering, impeded
oxygenation of the blood, the contractions of the heart diminished,
intermission or slowness of the pulse, the colour of the hands and
arms brown, livid or black, laxity of the muscles, hæmorrhagies
anxiety, coldness of the extremities or of the whole body, stupor,
coma, delirium, suffocation, and death frequently direct on the
first attack ; the blood in a like condition as in submersion or sus-
pension.-Though the effects now enumerated seldom all occur
in any one case, some or other of these symptoms will occur,
more or less, in different persons, dependent on the concentrated
form in which the cause is applied, the duration of its continuance,
and the facility with which the patient's constitution accommodates
itself to the operation of such a new stimulus. And in this way it
is, that of a number of individuals, labouring under the influence
of causes of this sort, in like situations and circumstances, one
shall have an aggravated, another a mild, and a third no disease
whatever: and so on in all possible degres of violence or mildness.
For a more clear and satisfactory illustration of these remarks,
I shall select, from medical history, a few well marked and deci-
sive instances of diseases induced by breathing an air thus vitiated.
Chisholm's
* See Appendix, Note D.


( 31 )
Chisholm’s* history of what he calls an uncommon epidemic
fever observed in the island of Grenada, may be considered as a
fair exemplification of the effects produced by this modification of
atmospheric air, mingled perhaps with other non-respirable airs,
and acting on the lungs of the soldiers, sickening in the barracks of
St. George's, a remarkable unhealthy spot, surrounded by marshes.
" The general type of the fever was that of a quotidian intermit-
tent, but so extremely irregular as not to admit of a reference to
any of the common species. It was truly anomalous, and so in-
sidious as to endanger the life of the patient before any apprehen-
sion could be entertained of its fatal tendency. In almost every
case, the patient seemed in a state of very great anxiety at all times,
with eyes inflamed, and a little protruded; a strong expression of
depression of spirits in his countenance; a very great degree of de-
bility, and a sense of weariness, as if he had undergone excessive
fatigue. But the symptoms which most troubled the sick, during
both the paroxysm and the intermissions, if they can be properly
called such, were an intolerable headach, with a throbbing of the
temples, and a lethargic heaviness. During the intermission,
whilst the patient was labouring under all, or most of these symp-
toms, his skin was preternaturally cool; his pulse small, quick, and
hard ; and his whole body covered with a clammy moisture. The
paroxysm generally came on sometime between eight and twelve
at night; and its approach was indicated by a very great increase
of the coldness, with shivering. These were soon succeeded by
violent heat, increased anxiety, and headach, and very frequently
by delirium. It continued two, three, or four hours, and termi-
nated in profuse diaphoresis; but contrary to the usual form of in-
termittents, on the ceasing of the diaphoresis, the patient continued
afflicted with anxiety, headach, &c. to the degree I have men-
tioned. The paroxysm, in some, was marked with infinitely
greater violence than in others. In the case of one soldier, the
paroxysm began about twelve o'clock at night, with all the most
violent symptoms, at once a deadly coldness of the body, and ex-
cessive delirium. These, constantly increasing, terminated, in
about two hours, in total insensibility, coma, and death. In a few
cases, very little intermission could be perceived throughout the
whole course of the disease: in these there was a continual alter-
nate succession of shiverings and flushings, with a disagreeable
clamminess on the surface of the body, which never afforded relief.
When, in such cases, any thing like distinct intermissions could
be observed, they occurred at or a little before noon, and continued
one or two hours ; but in the others, the periods of shivering and
diffusion
* See Duncan's Medical Commentaries for 1792, p. 267, et seq.


( 32 )
diffusion of heat returned so rapidly, that scarce any interval could
be perceived. The prostration of strength, brought on by them,
was astonishing; and it was observed too, that the patients who
laboured under the disease in this form, had a much more ghastly
countenance; sighed and moaned more ; were infinitely more rest-
less; were more subject to raving, and had more of a dirty, yellow
suffusion over the skin, than the rest.
" In most of the cases respiration was extremely difficult; and on
ordering the patients to make a deep inspiration, they were sudden-
ly checked by pain more or less acute, which, however, they could
not refer to any particular place; except in a few instances, when
it was found most troublesome at the pit of the stomach, stretch-
ing to the hypochondria and spine. Some also complained of a
rawness, as it were, from the throat to the stomach; or, as they ex-
pressed it, " a rawness and burning of their inwards."
" A yellowness on the skin was by no means a constant symp-
tom. The suffusion was general over the body; sometimes of a
deeper hue, and sometimes particularly about the eyes, and on the
neck, approaching to a livid colour.
" Dissections, in these cases, proved the whole intestinal canal to
be sound."
Lind* gives an account of a disease, operating pretty much in
the same way, though with less violence, on board several ships
in the British navy, in 1759. " The fever which raged in all
these ships, greatly affected the breast. Some who were seized
with it, as if they had been under a salivation, spit up six or eight
pints of a thin phlegm, in forty-eight hours; and, to prevent suffo-
cation, were obliged to have their heads supported by pillows.
Their blood was extremely viscid and glutinous. This I observed
even during the last stage, in a person from whom it was then ne-
cessary to take blood for a pain in the breast, greatly impeding res-
piration. The head was affected often with a heaviness, and dull
sense of pain, seldom with a delirium. Cough, spitting, and
pricking pains of the breast, were the most universal complaints,
&c. The attack of this infection begun with shivering, suc-
ceeded either by pain of the head or breast; seldom by an univer-
sal pain in the limbs, but most frequently by a tightness of the
breast and cough, which last raised the acute pains in the chest.
Several who recovered were afterwards distressed with a dulness of
hearing; many relapsed. A midshipman, after being able to sit
up for several days, fell again into the fever, which was accompa-
nied with convulsions, and expired in thirty hours after the last
attack, when his body was found covered with patechiæ : a few
died
* Dissertation or Fevers and Infections, Ch. I.


( 33 )
died consumptive, being exhausted by the vast discharge in spit-
ting. In four or five persons, there were symptoms, of malignity;
and out of above an hundred patients received into the hospital,
from those ships, eight died of the fever. The distemper, if it had
occured elsewhere than in the ships, might perhaps have been
judged solely inflammatory, and to have proceeded from causes
very different from the teal ones."
Fordyce, in his dissertation on simple fever,* has the following
observations, which tend to the corroboration of this argument.
" When the attack is fatal, it sometimes kills in five minutes:
sometimes it requires half an hour; sometimes longer than that
time. While the patient is yet sensible, violent headach, with
great sense of chilliness, takes place; the extremities become cold
and perfectly insensible; there is great prostration of strength, so
that the patient is incapable of supporting himself in an erect pos-
ture. He becomes pale; his skin of a dirty brown, and he is soon
insensible to external objects: the eyes are half open; the cornea
somewhat contracted, and the patient goes off very soon : the pulse
is diminished, and at last lost, without any frequency taking place;
but if it be long before he dies, the pulse becomes excessively small
and frequent," &c.
The effects induced by exposure to an atmosphere, charged
with the causes of these diseases, as pointedly elucidating their ope-
ration on respiration, may be seen in  Mr. Martin's account of
the air of some parts of Bengal. †
It may not be amiss, in this section, to investigate the operation
and influence of these causes on brute animals.
From the production of diseases in the human constitution, by
exposure to marsh miasmata, and other like decompositions of ani-
mal and vegetable snbstances, it may appear highly probable that
the rot in sheep, kept in low grounds, is analogous to the intermit-
ting, and like diseases of the human species, and excited by the same
cause. And a like investigation might prove that the bloody mur-
rain, which prevails occasionally among cattle, is occasioned by a
similar contagious cause, operating and producing an affection
similar to our dysenteric fever, &c.
But that, while our habits suffer the operation of these causes in
their superior degree of operation, brute animals have analogous
experience, may be inferred from the following facts :-
Sorbait, of Vienna, relates, that during the plague, " larks, so
numerous in Austria during the autumn, were wholly wanting,
so that not a single one could be met with; and tame birds, kept in
E cages,
* Page 181.
† See Appendix, note B.


( 34 )
cages, all died. Homer* mentions the death of dogs and mules,
as the forerunners of the pestilence in the Grecian camp before
Troy. Thucidides † observed the pernicious and deadly effects of
the atmosphere, during the plague at Athens, in the second year of
the Peloponesian war, upon birds and beasts, and particularly on
dogs.
Facts of this kind were not wanting during the prevalence of
our late epidemic. It is stated to me, from undoubted authority,
that at the Belvieu hospital the fowls and chickens, which fed about
it, and like other poultry, came occasionally into the hospital,
(perhaps drank, and picked up crumbs about the house,) all
suddenly died without any ostensible cause; on dissection, the ap-
pearances were similar to those of the human species who have died
of putrid diseases. And in a part of the city, where there existed
comparatively, a small proportion of the epidemic influence, the
ducks kept in yards, and which received the usual attendance, as
to food, all died off in such a manner, as to excite the remarks and
surprize of the inhabitants.
Fowls, in some of the yards, sickened, and some died; but after
a while, the survivors experienced no inconvenience. Bruce
mentions the deadly effects of the Simoom blasts, in the African
deserts, upon all breathing creatures. Cleghorn observes, that in
some of the valleys of Minorca, beasts, as well as men, suffer ;
and it is related by respctable authority, that horses have been in-
commoded by the autumnal air of Onondaga, for some time after
being carried on to the low lands.
SECT. II.- On the Alimentary Canal, or Stomach, and Intestines.
How the aforesaid Septous Combinations may be conveyed into the
Alimentary Canal of living Animals; or generated there from the
Corruption of the Food; and of the Effects they produce in both Ca-
ses, by acting on the Stomach and Intestines.
I. FROM the properties of the causes of contagious and infec-
tious diseases, then, we infer the occasional operation of these in
the alimentary canal, by their introduction by the saliva and wa-
tery parts of our food: in corroboration of which mode of opera-
tion, we are presented with the following reflections and facts
from their respectable authors:-
Gardiner observes that the manner in which  the causes of cer-
tain malignant fevers, arising from marsh miasmata, human or
specific contagion, get into our habit, is by the noxious effluvia
taken in with the air in respiration, mixing with the saliva,
and,
* Iliad. i, 69.
† Book ii.


( 35 )
and, by deglutition, conveyed into the stomach, where by
certain changes wrought on the gastric fluids, and their parti-
cular stimulus on the nerves of the stomach and bowels, they
prove the cause of fevers, differing from one another according
to the nature of the infectious exhalation. " This I have always
thought to be the most probable way that infections are received
by us, and of their acting on our system, in the production of
fevers."*
This opinion of the miscibility of the infectious effluvia of ma-
lignant fevers, with the saliva, and of its afterwards passing into
the stomach, is upheld by Turner, physician to the military hos
pitals in the West-Indies, in a letter to Sir John Pringle, who
says that he escaped the infection of the hospital fevers by chew-
ing tobacco during the time he was on his visits to the men in the
hospital, imagining that all putrid and contagious effluvia entered
and infected by the saliva, which he took great care not to swal-
low whilst he visited the sick.†
Lind believed in this mode of receiving contagion, who says,
" Swallowing the spittle in infected places is justly deemed a
means of sooner acquiring the taint, upon which account neither
the nurses nor any one else should be suffered to eat in the hos-
pital." ‡ And he relates an occurrence which may unquestiona-
bly be instanced as operating in this manner-“ A company of
gentlemen belonging to his Majesty's ship the Phœnix, taking the
diversion of hunting and shooting at the mouth of the river Gam-
bia, by following their game into a large swamp, were all of them
affected by its putrid effluvia. They were immediately siezed with
sickness, vomiting, headach, and a constant hawking and spitting
from a disagreeable smell which (as they express it) seemed to re-
main in their mouth and throat. Upon returning to the ship,
each of them was ordered a vomit, which immediately removed all
those complaints." §
And again, ‖ "I am apt to think, that an infection from what-
ever impure fountain it is derived, does first discover itself by af-
fecting the stomach and intestines."
Balfour's opinion corroborates this argument, as we have seen
in our collection of observations and facts proving the identity of
cause in the production of fever, and certain other diseases. ¶
Rush
* Animal Economy, p. 196.
† Med. Annot. vol. v. p. 472.
‡ On Hot Climates, p. 111.
§ On Hot Climates, p. 138.
‖ On Fevers and Infections, part 2, p. 65.
¶ See p. 23.


( 36 )
Rush* relates, that "in small rooms crowded, in some in-
stances, with four or five sick people, there was an effluvia that
produced giddiness sickness at stomach, a weakness of the limbs,
faintness, and, in some cases, a diarrhœa.”
Mitchill relates an instance of a gentleman who received the
fumes of a dysenteric purging: some uneasiness of the stomach,
and qualmishness, came on, which, in a few hours, ended in a
looseness. A similar indisposition was brought on in another, by
receiving the fumes of a corrupting corpse. In both these in-
stances, it appears as if the infection was swallowed with the saliva,
and thus operated as a purge.
Mr. Van Eems† informs us, that if the abdomen of an animal
that has laid some time under water after drowning, suddenly
burst, a most active and penetrating fluid proceeds from it, very
injurious to the eyes, lungs, and stomach; and instantly destruc-
tive to the appetite, insomuch as to provoke nausea, vomiting, and
even to bring on dysentery.
2. Another mode in which the diseases dependent on those causes
may be produced, is by the disorganizing process, which the ingest a
take on, in the stomach and bowels themselves.
The human constitution derives its principal support from fo-
reign materials, received into the digestive organs: and the due
performance of this necessary function is therefore indispensably
requisite to the healthy condition of our bodies: this state is pre-
served by the influence of the gastric liquor and saliva in the
stomach, and by the pancreatic and bilious juices in the small
intestines; but these healthy secretions are again dependent on
the vigour of the organs of digestion, which is increased or di-
minished by the matters taken into them. These substances are
derived from the animal and vegetable kingdoms, and in healthy
digestion, will they sustain and nourish our systems.
But in cases of the prevalence of epidemic, and other like
diseases, while the predisposing causes exist, it would be to be in-
ferred, from our principle, that flesh-eaters, in an especial degree
should be liable to an attack of those diseases; for, from the analysis
of the lean muscular fibre, we are enabled to understand whence
may flow the septon, for the formation of the deleterious cause;
and by the occasional use of vegetable substances, as well as from
the animal matter itself; the other ingredient, oxygene, is afford-
ed. A consequence is, that those substances which are defici-
ent in either of the component ingredients, are those of the
most salutary use in such cases: substances of this nature are
the
* On the Remitting Bilious Fever of Philadelphia, 1793, p. 107.
† Prælection. Boerhaav. 248.


( 37 )
the fat of animals, oil, butter, &c. which, are known not to
contain the septous or putrifying base, and may therefore be
had recourse to as food, with the most perfect safety; or, on
the other hand, vegetables, as affording less septon than lean
meats, and some of them scarcely any, may be used with like
freedom. And it is unquestionably owing to this mode of living,
that Frenchmen are comparatively in so small a degree, sufferers
from these forms of pestilential ailment, in unhealthy countries and
climates ; whose habits of life are such, as to draw by far the great-
er part of their nourishment from vegetable substances. To this
effect, Jackson* observes, that " the French and Spaniards eat less
animal food, and drink their liquors greatly more diluted, than
the natives of England : they escape better from dangerous dis-
eases, and this has been remarked to bear some proportion to the
degree of abstemiousness they observe."  Mr. Verdoni declares,
that " the Greek christians in Smyrna, during the season in Lent,
when they eat only vegetables, are very seldom attacked by the
plague, while among those who eat flesh the contagion makes
great havock. Thence the best means of prevention are to eat
moderately, and not at all of animal food," &c.
In infected situations, those causes which tend to the debi-
lity of the digestive organs, will contribute very much to the
production of disease. Of this kind are the habitual use of too
much ardent spirits, and other habits of intemperance; exposure
to excessive heat, and other violent exciting powers, which, by
their operation, induce an indirect debility of these organs; or
the operation of fear, terror, and the like, may induce a simi-
lar operation, by an abstraction of the usual necessary stimula-
tion. These favour the unhealthy disorganization of the ingesta,
by withholding the antisceptic powers of digestion and concoction,
depending upon a healthy state of the gastric secretion. When,
by the operation of the above-mentioned noxious causes, this un-
healthy and debilitated condition is induced, it is evidenced to us
by tension, oppression, and belching; and still further, by the acid,
putrid, and pestilential nature of the matters vomited from the
stomach.
That an acid is vomited up in cases of this nature, is ascertained
by the sour taste, and by the erosion of the calcarious enamal of
the teeth, in some instances. " I have," says Hunter, † " seen
an instance of fever, in whieh it was necessary to give from half
an ounce, to six drachms of the powder of oyster-shells, to destroy
the acid that was generated in the course of the day, which other-
wise
* Fevers of Jamaica, p. 395.
† Observations on the Diseases of the Army in Jamaica, p. 161.


( 38 )
wise occasioned great pains and retchings." The green colour of
the bile is known to depend upon an acid in the stomach; for we
know by experiment, that the most healthy bile, whose colour is
yellowish, will be changed to green by mixture, in certain cir-
cumstances, with an acid.
What the nature of this acid is may be collected from the ac-
count given by Wallis,*  of a porraceous and black bile often
seen thrown up by vomiting, which corroded metals, and boiled
up on the ground like spirit of vitriol dropped thereon; and so
austerely acid, that it set the teeth strongly on edge, and excori-
ated the throat. It is further related, that a man who had vomit-
ed up a large quantity of green, black, and acid bile, being agi-
tated by convulsions, had a silver spoon put into his mouth, that
he might not bite his tongue, and in a moment it turned black as
if it had been stained with spirits of nitre; but the man had drank
liquors soured with lemon juice.
The coffee coloured matter, commonly called the black vomit,
which is ejected from the stomach in violent remitting fevers and
plague, is to be considered as bile, impregnated with the more ac-
ive septous combinations, as appears from its corrosive na-
ture, noticed by dissectors in these diseases; or yet, in other
cases, there is an admixture of blood, while by its own caustic na-
ture the septous acid thus formed in the stomach, had eroded the
extreme blood-vessels of that viscus. Hillary † witnessed the ex-
istence of these appearances in the remitting fevers of Barbadoes,
who observes, that " great quantities of black, half-baked, or
half-mortified blood, are frequently voided, both by vomiting and
stool; with great quantities of yellow and blackish putrid bile,
by the same ways."
When, therefore, there exist such fluids in the stomach, the oc-
currence of nausea, excessive vomiting, painful burning of the
stomach, and other symptoms of Gastritis, we should scarcely
doubt from the nature of these septous combinations, that on
dissection, the various phænomena of inflammation would ma-
nifest themselves.
Conformably we find, according to the dissections of Drs. Phy-
sick and Cathrall, that in the disease of Philadelphia, in 1793,
" the stomach and beginning of the duodenum, are the parts that
appear most diseased. In two persons who died of the disease on
the fifth day, the villous membrane of the stomach, especially about
its smaller end, was found highly inflamed: and this inflammation
extended through the pylorus into the duodenum some way.
The
* Edition of Sydenham, vol. ii. p. 191.
† Diseases of Barbadoes, p. 151.


( 39 )
The inflammation here was exactly similar to that induced in the
stomach by acrid poisons ; as by arsenic, which we have once had
an opportunity of seeing in a person destroyed by it.
" The bile in the gall-bladder was quite of its natural colour,
though very viscid.
" In another person who died on the eighth day of the disease, se-
veral spots of extravasation were discovered between the mem-
branes, particularly about the smaller end of the stomach, the in-
flammation of which had considerably abated. Pus was seen in the
beginning of the duodenum, and the villous membrane, at this
part was thickened.
" In two other persons, who died at a more advanced period of
the disease, the stomach appeared spotted in many places, with
extravasations, and the inflammation disappeared. It contained,
as did also the intestines, a black liquor, which had been vomited
and purged before death. This black liquor appears clearly to be
an altered secretion from the liver; for a-fluid, in all respects of
the same qualities, was found in the gall-bladder. This liquor
was so acrid, that it induced considerable inflammation, and swel-
ling on the operator's hands which remained some days. The
villous membrane of the intestines in these last two bodies, was
found inflamed in several places."
And in a letter addressed to Dr. Duffield, of Philadelphia, from
Professor Smith, we extract the following appearances on dissec-
tion, of one who died of our epidemic, in 1795: " The stomach
and duodenum exhibited marks of high inflammation; the liver
little altered from its natural appearance: the gall-bladder absolute-
ly empty; the lower intestines quite sound, the lungs also: and the
brain, except in being rather of a darker shade than is usual."
From these dissections it appears, that the superior portion of
the intestinal tract, is the part which more particularly suffers the
operation of these causes of disease. And hence we are led to an
inquiry into the causes which may account for this partial opera-
tion. From the nature of these septous combinations, which are
supposed to be the offending causes in these situations, we are na-
turally led to inquire into the component ingredients of the bile,
which is here emptied into the intestines; in order to ascertain if
there does not exist in it some substance, for which the principle of
putrefaction has a greater attraction than for the viscera themselves.
From the succeeding experiment of Saunders,* we analogically
conclude, that such a substance does exist in the biliary secretion
of the human species; as there is probably no very material dif-
ference in us, from other animals, in this secreted liquor.
" A quantity
* Treatise on the Liver, p. 103. London, 1793.


( 40 )
" A quantity of (ox) bile and diluted marine acid were put into a
flask, and placed in a sand bath, until they had acquired the boil-
ing heat. On inspection, the separation into parts was very
evident; and on committing it to the filter, it separated a colour-
less fluid, destitute of every bilious property. The residuum con-
sisted of a very dark green mass, intensely bitter, and extremely
glutinous. When examined, it appeared to be composed of
an animal mucilage, in combination with a resinous substance.
" But to ascertain in what way the acid had effected the decom-
position, it became necessary to examine the filtrated liquor. It
was therefore subjected to a cautious evaporation, and at a proper
period was suffered to cool.
“ Under cooling, chrystals were formed of a cubic figure, which
decrepitated by heat, and possessed all the characters of common
salt.
" Therefore the decomposition was here occasioned by the ma-
rine acid engaging the mineral alkali, which it separated from the
other elements of the saponaceous body, and, by uniting with
that basis, formed common salt."
Since then there is existing in our intestines, this bilious secre-
tion, whose alkaline nature we have thus seen experimentally as-
certained, it will appear manifest from the known attraction
between the acid of the stomach and the soda of the bile, in
what manner there shall take place a union of the septous acid
with the biliary alkali, and thus a considerable part, or in some
cases even the whole of the septous acid, being thus neutralized
or saturated, that part of the duodenum below the opening of the
ductus communis choledocus, together with the jejunum and ilium,
in most instances, be unmolested by its inflammatory and caustic
nature. These facts lead to a satisfactory solution of the phæno-
mena of the extraordinary secretion of the bilious matter in those
diseases; since it appears, from the preceding considerations, to
be one of the resources of nature, in counteracting this offending
cause.
Or, if it should not meet with a substance to neutralize it whol-
ly, or nearly so, it may pass on, and by the operation of the ab-
sorbent vessels, by being taken up and carried the round of the
circulating fluids, be eventually manifested by imparting to the
skin a yellow, or other like suffusion : this explication of the tinge
of the skin, in certain instances, is rendered probable, by the re-
lation of a case of disease last summer, from undoubted authority,
in which the following striking fact presented itself: A patient
labouring under the epidemic, whose skin was of a remarkably
yellow color, was ordered an epispastic ; on dressing the blis-
ter


( 41 )
ter after its operation had ceased, the scissars which were made
use of to remove the scarf skin, were accidentally left moisten-
ed with the serum for about a quarter of an hour, when, on exa-
mining them, the observer was astonished to find they were oxy-
dated as if dipped into a strong mineral acid.
And Van Swieten, in the plague of Oczakow, relates, that " the
instruments which the surgeons made use of, were turned as black
and livid as if they had been dipped in aqua-fortis."
SECT. III.-On the Cuticular Surface.
How the Skin of Persons, living in an Atmosphere thus vitiated, is af-
fected, and how it operates on Wounds.
ON the application of the causes of disease which we have
been considering, do we presume, are to be explained various ef-
florescences and eruptions, occasionally besetting the external
surface of our bodies. These appearances will be differ-
ent, according to the concentrated or sparse form in which the
causes are applied, and to the duration of their continuance; and
in this way partly is to be explained, the peculiar tinges of the
countenance in tropical climates; even although there shall not
be present actual disease.* And, on the like principle, is expli-
cable the absence of the different suffusions in contagious diseases,
till some progress has been made in the morbid action.
To this mode of operation, are probably referable the different
kinds of eruptions, which have been hitherto considered as criti-
cal depositions of humours from the body. From the greater spe-
cific gravity of the contagious fluids, the lower parts of the body,
which are most constantly exposed to its operation, are first affect-
ed, and worse afflicted than other parts of the constitution. Thus
the legs of persons sick on ship-board, are often miserably ulcerated.
Sometimes, in very unhealthy countries, an uneasy itching in the
legs, has been the first symptom of disease, and upon pulling down
the stockings, streams of thin dissolved blood followed; soon after
which a ghastly yellowness invaded the whole  body, and the pa-
tient has died in less than forty-eight hours.
In 1764, the quality of the air at Batavia, which then exhibited
a mingled scene of disease and death, was so malignant, that a slight
cut of the skin, a scratch of a nail, or the most trifling wound, &c.
generated quickly into a putrid spreading ulcer, which, in twen-
ty-four hours, consumed the flesh even to the bone, as was expe-
rienced by the British frigates Medway and Panther, then lying
there. From its disposition to adhere to bedding and clothing,
F there
* See Appendix, note E.


( 42 )
there can be no difficulty in understanding how miliary and pe-
techial spots are produced, in many instances beginning about
the back, loins, and inside of the thighs of those who are exposed,
and extending thence over the covered parts of the body, in those
who are sweating in their own vapours and exhalations in bed :
they have thus a contaminated atmosphere around them; and,
from its operation upon the sick, do these morbid appearances of
the skin proceed. The occurrence of these sorts of fevers in low,
foul, and dirty dwellings, &c. may thus be referred to the noxious
air the patient lives in, and to the infected beds they lie upon.
In the island of Jamica* sores are very frequent and trouble-
some on the lower extremities. A trifling scratch, bruise, or hurt
on the feet and legs, soon became a deep and spreading ulcer, which
was always difficult, and sometimes impossible to be healed.
Little injuries of these parts, are very apt to spread rapidly, and
form a large ulcerated surface. Granulations are hard to form,
and when formed, frequently become flaccid and mortify, the
portion skinned over ulcerates afresh, and the sore becomes
larger than ever. The bones are apt to become carious, the pa-
tient to grow hectic, and linger on to death. Fresh vegetable diet,
full nourishing diet, calomel in smaller doses, to operate as an
alterative, external application of almost all sorts of poultices,
ointment, dry lint, &c. and a horizontal posture of the limbs,
were so ineffectual, that Hunter relates it as the general result of
all his experience, that ulcers of some standing, and of considera-
ble size, in the lower extremities, cannot be healed in that country,
by any means we are acquainted with. Yet these very patients
sent away from the island to Europe, had their ulcers frequently
healed on the passage; the rest, except in cases of carious bones
soon recovered. Amputation in these other cases answered in
England, but succeeded very badly in Jamaica.
Cleghorn† testifies to the analogy between Rome and Minor-
ca, in respect to the troublesome nature of ulcers, on the infe-
rior extremities. " Baglivi tells us, that at Rome ulcers of the
legs are almost incurable, and wounds in them difficult to heal,
while the like accidents on the head are quickly cured without
any trouble. The same thing happens here, insomuch that it is
a proverb among the natives, " Minorca is good for the head, but
bad for the shins."
 Van Helmomt ‡ saw a man, who, upon touching some papers
infected by the plague, felt instantly a pain, like the prick of a nee-
dle;
* Hunter on the, Diseases of the Army in Jamaica, p. 227.
† Diseases of Minorca, p. 78.
‡ Tum. Pest. p. 853


( 43 )
dle; a pestilential carbuncle made its appearance soon after, on
his fore finger, and he died in two days.
Van Swieten* relates, that a man who stirred up with his foot
the straw whereon the bed of one sick of the plague had been
laid, " a little while after felt an acute pain in the lower part of
his leg, just above the foot, as if the part had been scalded with
boiling water; the next day the epidermis, or scarf-skin, was ele-
vated into a large blister, upon breaking which a quantity of
blackish liquor run out, and underneath a latent pestilential car-
buncle was discovered."
SECT. IV.-On the Lymphatic and Glandular Systems.
How the above-mentioned Compounds operate upon the absorbent Ves-
sels, and the Glands of the Body.
ON these parts of our systems we are presented with the phæ-
nomena occasionally attendant on dissections of dead bodies,
from the peculiar gas thence arising, and of which an account is
given by Mr. St. John.† " I have known a gentleman, who, by
slightly touching the intestines of the human body, beginning to
liberate this corrosive gas, was affected with a violent inflamma-
tion, which in a very short space of time extended up almost the
entire of his arm, producing an extensive ulcer of the most foul
and frightful appearance, which continued for several months, and
reduced him to a miserable state of emaciation," &c.
A similar occurrence took place at the New-York hospital,
some months since, to two young gentlemen engaged in sewing
up the abdomen of a patient who had been examined by the
physicians and surgeons of that institution; each of them pricked
one of his fingers in the operation; in a few hours afterwards the
part pricked in both these instances, became painful and swelled;
the inflammation extended itself along the arm, till it reached the
axillary gland, on which it produced violent inflammatory action,
which was of some considerable continuance. In one of these
cases, the lymphatic vessels were so highly inflamed as to become
visible in the course of their distributions along the arm.
Rush ‡ notices like affections of this set of vessels, in the Phi-
ladelphia epidemic, of 1793. " I met with three cases of swel-
lings in the inguinal, two in the parotid, and one in the cervical
glands." And the epidemic of our own city, in 1795, afforded
some few instances of this sort.
The appearance of buboes in the plague, as remarked by every
writer
* Sect. 1409.
† Preface to Method Chem. Nomenclature, p. 111.
† Page 68.


( 44 )
writer on that subject, may be taken as the operation of these
causes on these parts of our constitution.
Nor are the brute animals exempted from the influence of these
stimulating powers when applied to their œconomy. For cats
and dogs have been known to suffer by the appearance of buboes,
&c. as related by the writers on plague, and other like maladies.
SECT. V.-A new Theory of Fever.
FROM the operation of these combinations the learned Profes-
sor of Chemistry has deduced a new doctrine of fever. Judg-
ing from their effects, pestilential fluids appear to be always, even
in their weakest form, somewhat of stimulants. In many instan-
ces, they are most violently so. Though their operation is modi-
fied in a very peculiar manner, when in a dilute form they impede
respiration, or nauseate the stomach, as they then bring on a dimi-
nution of action and energy, amounting in the cold stage to a state
of direct debility: when applied in great quantity and force, they kill
instantly ; when in less quantity,they produce an anomalous disease,
of the form of which Chisholm's cases present us with instances;
when in a weaker state, a common contagious catarrhal affection
may be the consequence; when inhaled in a form yet more diluted,
a remitting or intermitting fever may be the disease induced, of
the form of quotidian, tertian, or quartan, or any of their varie-
ties ; or the remitting may be called jail, hospital, ship, camp, ar-
my, yellow, putrid, or bilious, malignant, pestilential, miliary,
petechial, ardent, slow, continued, continual, dysenteric, contagi-
ous or infectious, according to the circumstances  that may occur in
the progress of die disease.
" The main difficulty left is to account for the cold fit of a regu-
lar tertian. This stage of fever, I believe to depend upon impeded
respiration; and the impeded respiration to depend upon the viti-
ated quality of the air, taken into the lungs; or in some slighter
cases, where the stomach is originally thrown into a disordered
state, the lungs, by association with that organ, are thrown into
disorder too, and for a time perform their functions  but imper-
fectly.
" Thus I presume it is, that the impeded state of respiration is at-
tended with a smaller evolution of heat and oxygene in the lungs;
and consequently with more or less diminution in the circulation
of the blood, and a proportionable degree of chilliness and coldness
throughout the body. The duration and degree of the cold fit
will correspond to the continuance and power of the causes dis-
turbing the pulmonic organs, either by acting upon them directly
or indirectly, through the intermedium of the stomach.
" From


( 45 )
" From the small quantity of heat and oxygene communicated to
the blood in the lungs, and the consequent slow and feeble circu-
lation of the blood, can the shrinking, paleness, tremors, cold-
ness, debility, &c. &c. be sufficiently explained, as the constitu-
tion is now deprived of its two chief stimulants.
" But why does not the continued operation of the vitiated air
upon the lungs, or the associated condition of the lungs with the
stomach, go on in an increasing series even unto death? The
power of our constitutions to become familiarized to the action of
noxious causes, is evinced by the innocent operation of poisonous
substances, which, by frequent repetition, grow gradually habitual,
and by custom, lose their primary operation. This disposition
to become familiarized to vitiated airs, is apparent in the inhabi-
tants of Africa, who are so seasoned to the air and climate
they live in, that it excites no disturbance at all in their
constitutions, while strangers fall victims in the greatest abun-
dance. Now, common intermitting paroxysms, are instances of
temporary seasonings, which the constitution experiences, of a
kind quite analogous to what is perpetual with the Guinea negroes.
" The cold fit sometimes does terminate in death; and this hap-
pens when the constitution cannot acquire the habit of enduring
the noxious cause with impunity. In the generality of cases, how-
ever, the stimulus of the infectious gas loses its power to operate
before the constitution is debilitated to death; and as soon as it
becomes, for this time, so much accustomed to the vitiated air, as
no longer to be disturbed by its presence, the cold fit ends. The
length and violence of the cold fit will thus be ceteris paribus, in
a compound ratio of the impediment given to the respiration by
the infectious gas, and the facility with which the constitution ac-
commodates itself to its action : if three persons then inhabit one
house, it is possible that one may become so quickly accustomed
to the air, as to have no distemper; a second may have a moderate
disease of but a few fits; while the third, possessed of a constitu-
tion not easily moulded to a new habit, may be incommoded by a
violent and obstinate malady.
" In every paroxysm of an intermittent, the infection thus wears
itself out; but this is only a temporary reconcilement of the body
to its action; when, after a repetition of fits, the disorder becomes
milder and milder, and after a while wholly ceases. This is a case
of lasting reconcilement; and in this way may a large portion of
small intermittents cure themselves, while the credit is given to
the bark ! This power of habit daily does wonders, and labours
more effectually for the good of the sick than bark, opium and
antimony put together.
" The


( 46 )
“ The attack of these causes being thus for a time overcome,
respiration grows free, full, and frequent; because there is now a
greater appetency in the constitution for heat; more vital air is
decompounded in the lungs, and more stimulus is applied by means
of the increased heat and oxygene now in the blood, to the heart
and arteries; these stimuli operate more powerfully on account of
the accumulated excitability of the body; and a degree of excite-
ment is thence induced which sometimes ends in death, sometimes
causes delirium, and in almost every case, exceeds the healthy tem-
perature.
" The duration and violence of the hot stage, will be cæteris pa-
ribus, in a compound ratio of the excitability accumulated in the
cold stage, and the heat and oxygene evolved in the hot one.
When the excitability is exhausted by the operation of the stimuli,
the violence of action will cease, and the body glow cool.
" The doctrine of intermitting fever then, is briefly this : the vi-
tiated atmospheric fluid, by interfering with the pulmonic action,
brings on the cold stage, and would continue the same until its ter-
mination in death, did not the constitution, in the meantime, ac-
quire such a habit as to gain a temporary insensibility to its action.
This habit being induced, the cold stage abates by reason of the
state of direct debility, into which the body had  been brought ;
anxiety continues, and by the quickening of respiration, heat and
oxygene are set loose in the lungs, and becoming incorporated with
the blood, now warm, and stimulate every part with more than
usual power, and occasion the phænomena of the hot stage, which
terminates as soon as the accumulated excitability of the system
is exhausted.-The sweating stage follows of course, as in other
cases of the subsidence of violent action: for after a time, the ex-
hausted excitability of the animal system, allows excessive action to
go on no longer, the respiration grows more moderate and easy;
the heart beats with less frequency and force; the arterial contrac-
tions are also more slow and health-like; and, as the arterial con-
tractions relax, the hydrogene and oxygene of the blood now run
together in the extreme vessels of the skin, and form the moisture
which bedews the surface, and this afterwards flying off by evapo-
ration, cools by degrees the whole body down to its ordinary tempe-
rature : and, as the arterial extremities of the rest of the body be-
come dilated by the subsidence of excitement, the other secretions,
which had been generally suspended during the fit, now return as
before: after this, the constitution, so far accustomed to the breath-
ing such an atmosphere, regains its former vigour and functions, as
far as the exercise induced and functions injured during the seve-
ral stages will allow.
" The


( 47 )
" The interval between one fit and the succeeding one, will be
proportionate to the duration of the habit of resistance acquired.
Some persons thus experience but one fit, and all is over; for, un-
der the same circumstances they are never invaded by a second.
Others suffer two fits, or a succession of fits, and, after a while be-
come so accustomed to the stimulus, that, if always applied in the
same degree of strength, its effect is no longer felt upon the body;
in other instances again, so hard is it for the constitution to be
moulded into a settled habit of opposition, that after enduring a
great number of invasions, it becomes at length enervated and
worn down, so much as finally to die exhausted.
" The species of fever, whether quotidian, tertian, &c. will de-
pend upon the readiness or quickness wherewith the offending
cause gains a new ascendency over the body, or breaks the habit.
And to the mobility of the body, or ease with which the habit is
broken, is to be ascribed, as well the frequency of the returns, as
the duration and severity of the paroxysms.
" The anomalous cases of fever, which have puzzled physicians
to explain, and nosologists to arrange, are thus very naturally ac-
counted for; since, according to the variation of the cause, as the
noxious atmosphere may thicken or disperse, will be the variety in
the effect produced ; and, as there may be infinite gradations of the
deliterious cause, there may be endless varieties in the morbid
effect.
" And to this principle of the human constitution, I believe may
be referred all the febrile ailments from the most trifling intermit-
tent to the more serious remittent, and the solemn form of con-
tinued fever.
" Hence further may it be understood how a succession of fits,
long continued, may dispose the constitution to a repetition of
fits, even when the morbid cause is away: for though there may,
be a habit of insensibility produced to the vitiated airs, yet a habit
may, in the meanwhile, be established in the bodily motions of fall-
ing periodically into regular trains of action, even when the original
cause is withheld. Here then will be produced a habit of having
paroxysms depending on the particular inward state of the mov-
ing fibres, after the manner of temporary seasonings; while, at
the same time, there is a habit formed of resisting the active causes
(vitiated air) altogether, or of obtaining a permanent seasoning as
to them.
" The cold stage of a paroxysm is a state of direct debility, induc-
ed by the vitiated air breathed operating to subduct heat and oxy-
gene from the body; and its termination is by the stimulus of the
vitiated air being for that time worn out. The hot stage, which
begins


( 48 )
begins as soon as the temporary seasoning, is induced, is a state of
excitement brought on by the heat and oxygene now operating
upon the accumulated excitability with additional force.-The
sweating stage is formed after the subsidence of the excessive action
of the body, and the consequent enlargement of the diameters of the
vessels, whereby sweat is formed by the combination of hydrogene
and oxygene, and the other secretions proceed again, as usual, in
the several glands.
" The length of interval between the paroxysms depends upon
the strength of habit acquired.
" The frequency of their occurrence will be proportioned to the
facility with which a temporary habit is broken or gives way.
" The cold stage is the most dangerous, and persons dying in it
die of the direct debility induced by the vitiated atmosphere they
respire.
" The hot stage is less dangerous, and persons who die in it ex-
pire in a state of indirect debility. But, according to circum-
stances, death may happen in both the cold and hot stages.
" The sweating stage is a mere consequence of the cooling of
the body, after the preceding heat and excitement of it."
The simplicity of this theory, when put in competition with
the complex doctrines of preceding physicians," at the same time
that it causes our astonishment at their divergency from the fun-
damental laws of nature, flatters our judgment with its own ap-
proximation ; and as it does not take the mind into the fancied
reasonings of speculative hypothesis, neither does it deprive it of
satisfactory reflections on facts and nature. The powers of habit
and custom, though hitherto acquiesced in, in almost every action
of life, have not as yet been sufficiently considered in their rela-
tion to febrile phænomena. Hence have the most useless reme-
dies been brought into estimation, and acquired a reputation to
which they had no just pretensions; the disorder abated as soon
as the constitution had become habituated to the new stimulus,
and not because specifics were administered. Hence, though
blood be drawn off to the amount of upwards of an hundred oun-
ce, or calomel administered to the extent of sixteen hundred grains
in the course of one febrile indisposition, the patient may get well
in spite of both, as soon as the habit of resistance is formed.
APPENDIX.


( 49 )
APPENDIX.
[NOTE A.]
On the Manner in which the Materials of Dwelling-
Houses are affected by Septous Fumes and Combinations.
In a Letter from Dr. SAMUEL L. MITCHILL, to Dr.
EDWARD MILLER, of Dover, Delaware.
SIR,
SOME paragraphs and essays which have for some time past ap-
peared in our newspapers, and a number of queries proposed to
me by my private correspondents, concerning the production of
infectious air in houses, and its concealment in sundry substances,
of which the habitations of men are constructed, have determined
me to collect such facts as occurred to me on that subject, and
make them the matter of a letter to you. Your very obliging and
friendly favour, dated at Dover, the 15th of November, merited
a more speedy answer, but I am confident you will pardon my tar-
diness, when you consider that I have of late, like yourself, been
engaged in an inquiry, tending to alleviate some of the inconve-
niencies which result from our mode of living, especially in large
and populous cities.
And here I shall take it for granted, as proved in my treatise on
contagion and elsewhere, that the air of houses, tenements, and
dwelling places, is vitiated occasionally in a very alarming and
deleterious degree by the gaseous oxyd, or volatilized acid produ-
ced by animal and vegetable decomposition, which have been de-
nomited the nitrous. I have for some time been of opinion, that
an examination of the facts upon this point is an important de-
sideratum, both in philosophy and house-keeping.
The materials or houses may be classed under three general
heads, as they consist, 1st. of Earth; 2d. of Wood; and 3d. of
Paper.
1. The earthy materials of human habitations, whether of stone,
brick, or plaster, may be considered as consisting in the main, of
flint, clay and lime, the greater part of them being capable of re-
solution by analysis, into one or more of these elements. The
G flinty


( 50 )
flinty parts of a building, comprehending the stone and the sand
mingled with the mortar, are from their nature not capable of
uniting, in ordinary temperatures, with any of the common acids
in any of their forms, and therefore remain pretty much in their
original state as long as the house stands.
But the case is far different with the lime and clay. The opera-
lion of burning lime-stone to render it fit for the purposes of ma-
sonry, is principally to deprive it of the carbonic acid (fixed air)
with which, in its natural and crude state, it had been united. And
this kind of air is so abundant in the atmosphere, that as soon as
the calcined material, now converted to quicklime, is taken from
the kiln, it begins to recombine in a slow and gradual progress
with the fixed air, which had been expelled by the fire, and returns
to the state of mild lime. In this condition, of greater or less com-
bination with its original acid, it is worked up into mortar, and
employed as a cement. And after its application to the purposes
of brickwork or walls, lime may be considered as attracting its
lost fixed air as fast as circumstances will permit; and this process
may go on until a greater part of the lime is saturated. In this
situation the walls may remain an indefinite duration of time, un-
til the fixed air is expelled by some substance having a stonger at-
traction for lime than itself.
The habitations of men are known to afford such a substance,
and the septous (nitrous) exhalations extricated in rooms, are found
to displace the carbonic acid by virtue of a stronger attraction for
lime, and attach themselves to that calcarious basis in the form of
a nitrate of lime. There are several substances, such as the acids
of sugar and of sulphur, which have a stronger affinity to lime
than the nitrous acid has; but these rarely occur to disturb the
common process. The plaster then by degrees becomes charged
with the acid of salt-petre, attracted from the air of the chamber.
This operation may go on, in an old and foul house, until the
whole of  the lime is saturated  with the septous vapour, and can
take up no more.
These noxious exhalations being now no longer attracted by
the lime, must either circulate through the house, or combine
with some substance capable of fixing them. The clay of the
walls is a basis with which they are disposed in the next place to
join themselves. The nitrous acid, in the absence of the sulphu-
ric (vitrolic) has the strongest attraction for clay, of any; and the
combination of these two substances may thus go on as long as any
particles of clay retain a capacity to attract the acid.
In the progression of things, the clay and the lime become load-
ed with as much septous acid as they can possibly absorb ; and
after


( 51 )
after this the pestilential gas, finding no other material to form a
chemical union with, will be accumulated and diffused through
the room or house, penetrating the interstices of bibulous and po-
rous substances.
A fashion prevails in our newly constructed and elegant houses,
of making the walls of gypsum, or plaster of Paris. This substance
is a compound of lime with the sulphuric (vitriolic) acid. The sul-
phuric acid, as was mentioned before, possessing a stronger attrac-
tion for its calcarious basis than the nitrous possesses, cannot be al-
tered or dislodged by the septic vapours circulating in the
rooms. The lime of such walls will therefore remain for an in-
determinate time, in their original condition; and the foul gases
will immediately, and with greater readiness than in the case of
lime-walls, vitiate the air of the house.
Walls made of lime and clay, may be thus viewed as preventives
of infection, while those constructed of gypsum have no such salu-
tary operation. The reason of the wholesomeness of the former is,
they are constantly taking the matter of contagion out of circulation,
and fixing it it such a manner as to render it quite harmless. As
long as the walls preserve their attractive powers they render the
air of a room fit for respiration in proportion to the quantity of gas
they imbibe; when they cease to attract any more of it, the air
becomes less fit for animal life, by the surplus of gas unabsorbed.
To make houses healthy then, the walls of such as have stood a
long time, and have become highly nitrous, ought to be broken
down, and a fresh plastering of lime applied; or if this could not be
conveniently done, a white-washing, which is only a thinner coat
of plaster, should be frequently performed. The septic fumes will
then have something to attach themselves to, and be taken rapidly
out of circulation. An easy experiment will determine whether
the walls of houses suspected of being nitrous, are really so or not.
Take a quantity of the old plaster, pound it and steep it in water,
and add some potash to the mixture; if the nitrous acid is there, it
will quit its connection with the plaster and join the potash to
form nitre.
The existence of nitrous acid in old grave-yards, at the same
time it points out the almost sinful impropriety of burying the
dead near the habitations of the living, directs us also to a remedy
of the evil. If the coffin containing the corpse was filled up with
lime or potash, the danger of communicating infection at funerals,
and the unwholesomeness of burying-grounds, would in a great
degree be obviated. In like manner, the addition of the same
substances to the numerous privies of crowded settlements, would
have a powerful effect in preventing the ascent of deadly vapours
into


( 52 )
into the air, or their penetration to cisterns and wells of water
through the earth.
2. As to the timber which enters into the fabric of our houses
whether it be oak, pine, cedar, mohogany, or of any other kind of
wood, I know of no decisive facts evincing a chemical union be-
tween it and putrid vapours. But as all these materials are con-
siderably porous, there can be no doubt of their receiving into
their interstitial spaces a portion of the vapours which occupy the
rooms. The quantity imbibed will probably be in proportion to
their sponginess or laxity of texture ; and in this ratio may the
different kinds of wood be imagined capable of penetration by
foul steams. In most cases of this kind however, I apprehend
the contagious matter is in a very separable state, and ready on
slight occasions to manifest itself in its proper and distinct form.
From the readiness with which wood is penetrated by water, and
from the known property of water to act as the vehicle to con-
tagion, there can be no doubt of its entering pretty deeply into the
timber of our dwellings, especially those that are not covered with
a coat of paint. The covering the inside work of houses with
paint, by occupying the pores of the wood, will exclude the en-
trance of pestilential vapours, and thus far tend to their purity and
wholesomeness. It is said that ships have sometimes become so con-
tagious as to infect every successive crew with which they were
manned. This must in all probability have arisen from the noxi-
ous matter inherent in their timber. And I suspect the same thing
frequently happens in many ordinary houses inhabited by a succes-
sion of dirty tenants. Wood however would seem to admit or ea-
sy cleaning. Clear water will go a good way towards purifying
it. But the infectious matter may be, without doubt, extracted
from it by careful washing with a solution of potash in water (com-
mon lye) or by white-washing with lime, or even with clay.
3. The paper with which houses are adorned, is a material of
such open and spongy structure, that most fluids can easily enter
into it. Oil and grease very readily insinuate themselves into
paper. It very readily imbibes water, and in very considerable
quantity too. Smoke tarnishes it very quick. And the colours
of ancient records and books are not wholly to be ascribed to the
decay of the paper and ink, but in part to the impregnation of the
pages with foreign vapours. From these facts, shewing the rea-
diness and avidity with which paper combines with most liquid
and aeriform bodies, there can be little doubt of its possessing a
capacity, like wood and other porous substances, to receive con-
tagion among its filaments. But as paper possesses little or no
chemical attraction for pestilential vapours, they will not, change
their


( 53 )
their nature, or lay aside their peculiar qualities, by entering into
the interstices of the paper, but remain in a very loose sort of con-
nection, and exceedingly prone to detach themselves and sally
forth into action. This idea is countenanced by the facts told
concerning the catching of the plague by handling letters, which
in these cases were very probably damp, and by aid of moisture,
concentered more of the poison within them. Yet when I reflect
that the bibulous or absorbent quality of paper is the very cause
why it is fit for receiving the stains, marks, spots, and colours
which we impress upon it by writing and painting, it seems as
if it might attach and retain a considerable share of venom, even
in its dry state. Upon the whole, paper may be estimated as
possessing all the inconvenience of wood, and in a much more
considerable degree. Nor will this conclusion be invalidated by
the consideration that the paper is covered with paint, for this
layer of pigment is not mixed in oil, as in the paints applied to
wood, but it is generally water colour, and therefore greatly more
open and penetrable. Notwithstanding these objections to paper,
it may safely be employed in drawing rooms and parlours without
any sensible inconvenience or risque, but bed rooms and nurse-
ries, especially in crowded families and infectious situations, had
better be furnished with lime walls, and coated over with a cal-
carious white-wash from time to time: when families are small and
situations neat and healthy, it is wholly immaterial in which way
the chambers are finished; but where the contrary is the case, it
must be remembered that frequently changing the paper, will
scarcely prove a remedy of the inconvenience. On the subject
of paper, an interesting consideration is, what danger there may
be in receiving letters through the medium of the post-office, from
infected places. That paper may receive and impart infection, I
hold to be a settled fact: and I hold it to be no less a fact, that as
there is no chemical connection between the one substance and
the other, heat alone will disengage them. If a letter, therefore,
should be received under circumstances leading to a suspicion of
contagion, it should be held as near the fire, with a tongs, as possible
without burning it, and continued till it be thoroughly heated.
The gas will be rarified and volatilized by the heat, and will
chiefly, if not entirely quit its lurking place in the paper, which
may be unfolded and read with safety.
With great regard and attachment,
I remain, very unfeignedly, yours,
SAMUEL L. MITCHILL.
New-York, Jan. 20, 1796.
Dr. EDWARD MILLER.
[Note B.]


( 54 )
[NOTE B.]
Copy of a Letter from FLEMING MARTIN, Esq; chief Engineer at
Bengal, dated 1st of October, 1765.
IN regard to the intense and uncommon heat in this climate-
it has been for some time past almost insufferable.
The thermometer was seldom under 98, and the quicksilver rose
at certain times of the day to 104 degrees by the best adjusted in-
strument; nay, I have been assured by some gentlemen, that in the
camp, 500 miles distance, the thermometer often stood at 120;
but such a difference, I imagine, was occasioned by the badness of
the instrument.
However, it is certain, that nothing could exceed the intense
heat we felt, day and night, during the month of June. May and
July were little inferior at times, but afforded some intermission,
otherwise very great mortality must have attended this settlement ;
though we were not without instances of fatal effects in the month
of June, when some few individuals, in sound health, were sud-
denly seized, and died in the space of four hours after ; but con-
sidering the malignity of the climate, we have not lost many, and
I believe the generality of the people are not so intemperate as
some ears past they used to be; though, from what I have seen,
the best constitution, in the most moderate persons, is a poor
match against a fever, or other disorders, in this country.
I have been as free from sickness as any other person in the set-
tlement; but I cannot say that I have enjoyed myself in that de-
gree as to be an exception; for no man here is without complaints,
and life and death are so suddenly exchanged, that medicines have
not time very frequently to operate before the latter prevails. This
is generally the case in malignant fevers, which are here termed
pucker fevers, meaning (in the native language) strong fevers.
The rains have set in since the fourth of June. We call this
the unhealthy season, on account of the salt-petre impregnated in
the earth, which is exhaled by the sun, when the rain admits of in-
tervals. Great sickness is caused thereby, especially when the
rain subsides, which generally happens about the middle of Octo-
ber. The air becomes afterwards rather more temperate, and till
April permits of exercise to recover the human frame that is re-
laxed and worn out by the preceding seasons ; for in the hot pe-
riods every relief is denied except rising in the morning, and being
on horse-back by day-break, in order to enjoy an hour or little
more before the sun is elevated: it becomes too powerful by six
o'clock to withstand its influence ; nor can any kind of exercise
be attempted that day again till the sun retires, so that the rest of
the


( 57 )
me twenty-four hours is past under the most severe trials of heat.
In such a season, it is impossible to sleep under the suffocating
heat that renders respiration extremely difficult: hence people get
out into the virando's and elsewhere for breath, when the dews
prove cooling, but generally mortal to such as venture to sleep in
that air. In short, this climate soon exhausts a person's health and
strength, though ever so firm in constitution, as is visible in every
countenance after being here twelve months. I have lately been
informed by an officer of distinction, who was formerly an en-
gineer at this place, that being sent out to survey a salt lake in the
month of September, he found the sulphurous vapours so stagnated
and gross, that he was obliged to get up into the tallest trees he could
find to enjoy the benefit of respiration every now and then; he
added, that he constantly had recourse to smoaking tobacco, (ex-
cept during the hours of sleep) to which, and to swallowing large
quantities of raw brandy (though naturally averse to strong liquors)
he attributed his safety. However, on his return, he was seized
with an inveterate fever of the putrid kind, which he miraculously
survived; though others, who attended him on the survey, and
lived many years in the climate, were carried off at the same time
by the like fever.
[NOTE C]
On the Miscibility of Contagious Air with Water. In a Letter from
Dr. SAMUEL L. MITCHILL, to JOHN STEVENS, Esq.-Read
before the Agricultural Society of the State of New- York, February
16, 1796.
DEAR SIR,
AFTER I had satisfied myself of the composition of that par-
ticular kind of air, which is produced from substances putrefying
in places where heat and moisture concur to form new combina-
tions, my next object was to detect its particular qualities, and re-
lations to other bodies. And I have become persuaded that in
all its forms, this oxyd or acid of septon, is readily and entirely mis-
cible with water. By water I do not mean the pure distilled fluid
merely, but also the water of rain, snow, ponds, and marshes; and
occasionally of the ocean, as well as the fluids which, though cal-
led by other names, do still consist chiefly of water, as vinegar,
wine, spirits, &c.
Some of the interesting considerations which arise from this
chemical attraction between watry fluids and infectious air, I shall
endeavour to state to you in the order in which they rise to my
recollection,


( 56 )
recollection, in answer to your polite and instructive letter, dated
at Hobocken, September 25, 1795. In dependence upon this
single principle, a multitude of facts press upon the mind, and all
appear equally easy of solution.
1. It has been experienced in the neighbourhood of unhealthy
landings, in the East and West-Indies, that ships lying a small
distance off at anchor in the harbours, or at sea, have in no degree
suffered by the noxious quality of the air, which was very injuri-
ous to the settlement on shore. But there, as well as on the coast
of Africa, a boat's crew sent on shore, and staying the night, are
very commonly seized with sickness, which very commonly de-
stroys a number of their lives. The reason of which seems to be,
that the contagious air (septous oxyd or acid) produced from pu-
trefaction on the low and muddy banks of rivers, &c. is most con-
centrated at the place of its origin. Here, sailors tarrying long
ashore, are obliged, in uncleared countries, to hut themselves,
and sleep near the ground. From the greater accumulation of
contagious air near the surface of the earth, they must be more
particularly exposed to its action while lying down than when set-
ting up or walking about. By remaining for six or eight hours
in this manner immersed in such an atmosphere, and during the
time of sleep too, one may readily understand how they either
sicken on shore, or soon become unwell after getting on board.
They suffer by its action in four ways: 1. By landing where the
atmosphere is vitiated. 2. By lying near the ground where the nox-
ious gas is most condensed. 3. By remaining so long a time within
the sphere of its operation. 4. By going to sleep, that it may da-
mage the body in that unguarded state. In the vicinity of all
this destructive air, the ships escape for two reasons : 1. Because,
if the poisonous air should reach them, it would be in a rare and
dilute form. 2. Because, in passing over the water, so much of it
would be absorbed, that a very thin stratum would remain on the
surface, not many feet, or perhaps inches in height; so that little
or no inconvenience could result from it. Hence the service of
cutting wood, getting water, burying the dead, trading excursions,
exposure in open boats along coasts, &c. are extremely hazaradous
in many hot climates.
2. The experiments made at Portsmouth, Cadiz, Sardinia, Pensa-
cola, and in Guinea, have proved that ships anchored off a little
distance from places where mortal sickness rages on shore, afford
a most convenient retreat for those who are well, and allow an ex-
cellent chance of recovery to such as are sick. The security of
such places in unhealthy seasons, has led, very naturally, to the idea
of recommending floating factories to the merchants who have
trading


( 57 )
trading establishments on the sickly coasts of Africa, as at Cape-
Coast-Castle, the mouths of the rivers Senegal, Gambia, &c.
Mr. Dodge, a valetudinarean, who built an ark, as he called it, for
himself and family, to avoid the influence of the sickly season on
shore, has shewn, by experiment, how well a private gentleman may
be accommodated and enjoy his friends in a floating mansion, consist-
ing of a sleeping-room, dining-room, apartment for servants, kitch-
en, coal-room, wine-cellar, &c. The principle upon which such
places of abode are pronounced healthy is, that as the contagious
fluid is produced ashore, or from mud in the neighbourhood, a
ship or floating habitation cannot commonly be affected by it, on
account of its attraction for water. The ideas mentioned in your
letter are therefore rational and just, " That in seasons of infec-
tion, temporary stages be framed of dock-logs, and anchored off
the city, at a convenient distance from the wharves. On these
suitable apartments might be erected for the reception and accom-
modation of the sick. And, in order to prevent, as much as pos-
sible the accumulation of contagion, let the stages be multiplied as
much as they conveniently can, and placed at proper distances
from each other. The most important benefits would probably
result from an arrangement of this nature. By having a number
of them, situated as they would be, it would be very practicable to
keep them free from contagion, as they might occasionally be suf-
fered to remain unoccupied long enough to cleanse them properly.
The sick would be moved with the utmost ease and convenience,
without the aggravation of their cnmplaints by the jolting of a
wheel-carriage. The dead might instantly be disposed of, and the
danger of spreading contagion, and panic terror, by conveying
dead bodies through the streets in a hearse, would be prevented.
As the removal of a sick person to an hospital of this kind would
probably prove extremely salutary to himself, there would not
be that reluctance either on the part of the sick person or his
friends, to this necessary measure; and thus the efforts of the police
to separate the sick from the well, so far from meeting with oppo-
sition, would be aided and assisted by every body. The opulent,
no doubt, as a necessary precaution, would provide hospitals of
this sort at their own expence. Thus situated, every comfort, aid,
and convenience might be afforded the sick, and their friends
might attend them with scarcely any apprehension of danger.
These aquatic lazarettos might also be employed in another way,
probably to great advantage. The air of the city, during the hot
months, is extremely injurious to young children. Vast num-
bers are carried off every year, during the summer season, by dis-
orders of the bowels. It is truly astonishing what an immediate
H effect


( 58 )
effect a removal from the foul air of the city has on infants labour-
ing under these complaints."
3. The remarks of almost all observers agree in this point, that
the aerial vapours from stagnant water are seldom mischievous,
until evaporation has so far advanced as almost, or quite, to bare
some part of the mud or bottom. The reason of this is evident.
As long as evaporation goes briskly on, the evaporating surface is
kept cool, and putrefaction of course, advances but slowly. The
gas extricated below, mingles with the incumbent water, and for
some time, little or none escapes to taint the atmosphere. But as
the quantity of water shrinks, and the swamp or pool dries up, the
attraction of the atmosphere for the water being stronger than that
of die water for the contagion; the latter is discharged from its
connection, and floats about at large: the mud now grows
warmer, putrefaction advances, more infected air rises, and there
is less and less water to arrest its ascent. And thus the process
is carried on, until the want of sufficient moisture, to promote the
chemical action of bodies, puts a stop to the work, and sends forth
all the gas into the atmosphere. This explanation corresponds
exactly with the facts relative to its operation upon human bodies,
and the consequent production of sickness.
4. Rain falling briskly in showers is found to have a beneficial ef-
fect in seasons of contagion. Some of the most infectious distem-
pers we are acquainted with, have happened in times of great
drought. The suffering inhabitants of sickly places have experi-
enced sensible relief from showers, and have generally relapsed
when dry weather came on. To understand this, it may be pro-
per to consider the infectious fluid as having risen some distance,
more or less above the ground, and the drops of rain passing
through it as they fall. In a condition so favourable for union,
the rain attracts the contagion, and carries it down to the earth.
The sick are thereby relieved, and the well less exposed to dan-
ger. By and by the water evaporates, and leaves the infectious
fluid by itself to rise again and contaminate the air-Mortality
recommences. The natives of Africa are so sensible of some-
thing unhealthy mixed at times with water, that though they ge-
nerally bathe once a day, they never do it in the fresh river waters,
when they are overflowed by the rains; but prefer spring-water,
which flows pure from the interior parts of the earth. The first
rains which fall in Guinea, are supposed to be the most unhealthy,
and as evidence of their being impregnated with something more
than common, they have been known to render the leather of
shoes mouldy and rotten in forty-eight hours, and to stain clothes
more than any other rain. Exposure to rain, and gettiug wet
thereby,


( 59 )
thereby, are generally believed, says Hunter, to be productive of
fevers in the island of Jamaica. I have heard fishermen remark,
that exposure and wetting in a shower of rain, was more likely to
make them sick, than the regular attendance of their seins, up to
the waist or arm-pits in salt water, day after day. There is one
case, however, in which a fall of rain may be productive of sick-
ness. I shall give an example, as it occurs in Africa. During
the drought, the wide rivers of that parched continent, are shrunk
to narrow streams, and retiring to their channels, leave bare a
large part of the surface they usually overflow. The moisture
soon exhales, and leaves behind it a thick and solid crust of dried
mud. When the rains fall, they penetrate and soften this parched
crust, soak into the ground below, and set the whole into a pu-
trifying state. From the surface, which, during its dry condition,
no vapours had risen, now proceed noisome and noxious exhala-
lations, which produce the most violent sickness.
5. Clothes wetted with water, and hung to windward, are the
only known correctors of the violence of the Harmattan and Sami-
el winds. They may operate in two ways: 1. By mitigating the
excessive heat of these blasts by evaporation; 2. By attaching and
fixing the pestiferous matter they contain, or turning it aside by
reason of its inability to pass through a coarse wetted cloth. A
great variety of charms and preventives are used against infec-
tion. None of the smelling-bottles, bags, &c. for the nostrils,
seem to be of any service. If any thing of this kind applied to
the nose and mouth, can do any good in pestilential states of the
air, it is a cloth or sponge wetted with pure water, or some watery
fluid, which will allow the respirable air to pass through or along
it, and imbibe infection among the water inherent in the threads
or pores. But such a sponge or cloth should be often washed or
changed, and never suffered to dry; otherwise the collected con-
tagion set loose on the drying of the cloth, will be suddenly breath-
ed in greater quantity than if no such thing had been used. It is,
therefore, very questionable, whether even this application would,
upon the whole, be of any real utility.
6. Health has long ago been considered as greatly influenced
by the quality of water. The saline, earthy, metallic, and to a
considerable extent, the aerial qualities possessed by this fluid,
have been a great way investigated. From the readiness of con-
tagious gas to combine with water, there cannot remain a doubt
of its being conveyed into the stomach in large quantities, toge-
ther with our drink. Though this remark will only apply to the
water swallowed cold; for all that which is taken warm in teas,
soups, &c, has been deprived of the pestiferous air, by the opera-
tion


( 60 )
tion of a boiling heat. It will be observed that I am now speak-
ing of fountain, spring, and well water, as employed for domes-
tic uses; and not of rain water, which certainly contains it.
Fresh drawn water may be generally considered clear of it; but
water that has stood long in an infected house may be considered
very suspicious at best. During the extensive and mortal dis-
temper which prevailed in the vicinity of the Salt-Lake, the Se-
neka-Lake, and on Genesee, in the autumn of 1795, there
was a remarkable connection between sickly settlements and bad
water. Where the water was good, few people were unwell.
From the description of the uniform shore of the Chesapeak-Bay,
where springs of pure water are scarce, and where stagnant pools
are filled with frog's spawns, musquitoes, &c. it would seem that
the foulness of the water entered largely into the remitting fevers
of that region. And I think the same observation applies to
other tracts of country, similarly circumstanced all the world over.
7. Spittle and the fluids of the mouth, consist chiefly of water,
and therefore may be imagined to possess an attraction for septic
and contagious gases. The matter of infection thus getting into
the mouth, will almost unavoidably find its way into the stomach
with the spittle, in common swallowing, or during the degluti-
tion of the food, or be conveyed thither with the drink. By
this inlet many physicians have supposed contagion to be receiv-
ed into the body. The opinion is probably just. A gentleman
of my acquaintance received the fumes of a dysenteric evacuation;
some uneasiness at the stomach came on, with qualmishness,
which in a few hours ended in a looseness. A similar indispo-
sition was brought on in another person by receiving the effluvia
at a funeral, from a corrupting corpse. In both these instances,
it looks as if the infectious gas was swallowed with the spittle,
and thus stimulated the intestines. Nor do the alledged experi-
ments of swallowing without detriment the poisons of small-pox,
the viper, &c. in very small quantities, prove that all other com-
binations and modifications of contagion must be harmless.
These experiments, though true, are, however, no further true
than respects these species of venom ; and I own I should like to
see them repeated in larger doses. Be this matter, however, as it
may, one wholesome inference results from the facts before us,
that it is prudent to cleanse the mouth of all spittle, to hawk the
phlegm from the throat, and throw them out frequently, and to
avoid swallowing those fluids as much as possible in infected pla-
ces From the various affections of the mouth and throat, in
many fevers, there can be little doubt of the contagion's having
a deeper and more serious operation, than upon the mere secreted
fluids.


( 61 )
fluids. Do not aphthæ, sore-throats, erythematic affections of
the pharynx and gullet, arise from the local operation of this poi-
son? This manner of accounting for these symptoms, is, in my
judgment, more accordant to fact and reason, than any thing I
have yet met with; for, as to the received notions of eruptions
coming from the blood and inward parts, and breaking out upon
the surface of the "body, I think them a very lame part of our
pathology.
8. A long continuance of fogs, with damp and drizzling wea-
ther, has been found unfavourable in sickly seasons. The gra-
dual and slow precipitation of water from the air, keeps the atmos-
phere so moist, that the small drops of water floating in it enter
the lungs with every inspiration, and carry a portion of contagion
along with them as far into that organ as they penetrate. A
damp air may thus be said to give strength to contagion, though
a dry wind may spread the mischief.
9. From the same principle may be deduced an easy method of
purifying infected goods, apparel, furniture, &c. the most effica-
cious and easy method of cleansing which, is to wash them in fair
water. For this purpose the water should be cold, that is, of a
common summer temperature, at which range of heat the conta-
gion readily mingles with it. Linen and other things intended
to be washed, should never be put immediately into warm or hot
water, as the steam arising from thence, is found, by experience,
to be offensive and dangerous. After steeping and soaking awhile
in cool water, the goods may be washed out, and afterwards put
into boiling water, if judged necessary, with safety. The appli-
cation of this practice to the cases of persons actually sick, to the
purification of bedding, houses, &c. where sick persons have laid
or died, and to preventing the introduction of contagion from
abroad, is as plain as it is extensive; and this principle is corro-
borated by the fact mentioned in your letter, " That Europeans
residing in Constantinople, Grand Cario, &c. have found, from
long experience, that by passing every thing they receive, such as
food, &c. through water, it is effectually deprived of its power
of communicating contagion; or in other words, the pestilential
gas, adhering to its surface, is retained by the water."
10. In many cases of sickness, especially where patients are clad
in woollen, and lay on feather beds, covered by blankets, an atmos-
phere of contagious vapours may be imagined to surround and
closely invest them. The skin, especially of those not accustom-
ed to purify it frequently by bathing, is beset by the same fluid,
whose particles seem to inhere in its pores and duplicatures. The
long continued immersion of the sick in shirts and sheets, ren-
dered


( 62 )
dered damp by perspiration, is thus not only a most unclean but
infectious practice. The relief afforded to persons labouring un-
der indisposition from infection by plunging into cool water, or
what I prefer, wiping the whole body with a wetted cloth, again
and again, arises not so much from the abstraction of heat as by
removing the irritating and pestilent matter adhering to the sur-
face. The purification of the whole body, by clean water, appears
to me to be as necessary, in infectious ailments, as cleansing the
stomach and bowels by internal remedies; and, I had like to have
said, in some instances quite as beneficial. If the observance of
personal cleanliness in this respect was more frequent, and cham-
ber-baths, as among the French, more generally used as a part of
bed-room furniture, contagious distempers, I am persuaded, would
be far less frequent. The notion of its checking perspiration be-
ing founded on a false estimate of the animal œconomy, is too
idle to listen to or to refute: and what adds further to the truth of
the principle stated is, that washing the bitten part in cold water,
has been recommended as very efficacious in preventing the con-
sequences of the bite of rabid animals; and the latest West-India
treatment of yellow fever confirms the utility of the boldest use
of cold water, by dashing it over the head and shoulders with a
bucket; or if the infected person was unable to set up, by wrap-
ping him from head to foot in a blanket dipped in cool salt water.
Thus, Sir, we learn that if the ingredients of atmosphoric
air, (septous and oxygenous gas) the commonest things in nature,
do sometimes get into chemical combination, and produce a pesti-
lential or non-respirable fluid, there is also another thing, one of
nature's most plenteous productions, which seems in its pure state
to be a sovereign preventive of a large proportion of their mis-
chief.
With deep esteem and respect,
Believe me to be,
Very sincerely yours,
SAMUEL L. MITCHILL.
Plandome, Feb. 6, 1795.
JOHN STEVENS, Esq;  Hobocken.
[NOTE D.]


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[NOTE D.]
On the Decomposition of Contagious Air by Vegetation. In a Letter
from Dr. SAMUEL L. MITCHILL, to ROBERT R. LIVING-
STON, Esq; Chancellor of the State of New- York, and President
of the Agricultural Society.-Read before the Agricultural Society
of the State of New- York, February 23, 1796.
DEAR SIR,
EVER since the idea has been started of epidemic and endemic
diseases being caused by liquid or aeriform compounds of the prin-
ciple of putridity, (septon or azote) with the principle of acidity
(oxygene) in different proportions, it has appeared to me an inqui-
ry highly worth the making, by what process in nature such vast
quantities of noxious fluids are decompounded, or taken out of
circulation. In my letter to Dr. Miller, of Dover, dated January
20, 1796, I stated the facts which occurred to me, concerning
the absorption of this class of fluids by the materials of which houses
are built, particularly as respected the lime and clay of their walls ;
and in another communication of Feb. 6, to Mr. Stevens, of Ho-
bocken, I pointed out the considerations then present to my mind,
relative to their miscibility with water. By these modes of combi-
nation, some of those deleterious fluids are so damped or repressed,
that their hurtful powers are quite suspended, until, by a severing
of the connection they had formed with some other substance, as
with lime, clay, water, &c. they break out into action again.
Besides these processes, in which the contagious airs are fixed
or connected, so as to disappear for a time from circulation, there
is yet another operation in nature which is capable of utterly de-
stroying them, and resolving them into their constituent elements.
This operation is VEGETATION.
I was induced to this opinion by the following circumstance :
The scavengers and cartmen of the city of New-York are in the
habit of collecting from the streets large quantities of putrid mud
and filth, and of laying it in heaps on vacant lots, near the skirts
of the city, to be converted into manure. Near the ship-yards,
on the East river, in the neighbourhood of a number of these col-
lections of street manure, the yellow fever was very rife and de-
structive ; and in the opinion of the most observing inhabitants
a considerable share of its violence was owing to their vapours and
exhalations in the autumn of 1795. That putrid effluvia should
cause sickness, is a very ancient idea; but the acquiring a precise
idea of the nature of putrid effluvia, has at once such an intimate
connection,


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connection, both with agriculture and physic, as to render it a
matter of more than ordinary importance.
These heaps of manure appear to me to be nitrous soils, and ca-
pable, under proper management, of affording much nitrous acid.
The effluvias from nitrous soils in Bengal (Martin's Letter in
Meigs's New-Haven Gazette, May 22, 1788) and Spain, ( Town-
send's Travels) are themselves nitrous and very noxious. The
nitrous nature of putrid vapours appears from Mr. Thouvenel's
experiments, (Memoirs de l'Acadimiie Royale des Sciences, &c.)
and I think from Dr. Priestley's (2d Exp. and Obs. p. 217.)
The collectons of putrifying substances in the parts of New-
York more especially affected by that distemper, may be consider-
ed as so many smaller dung-heaps, and generating in like manner
a vast amount of nitrous exhalations. These, when afforded suf-
ficiently concentrated and copious, by the concurrence of suffici-
ent heat and moisture, produce yellow fevers, bilious fevers, &c.
and occasion great panic and alarm in society.
Now, these very substances that cause so much mischief and
terror in cities, are sought after with great avidity by farmers,
who purchase them at a high price, and use them with much ad-
vantage to fertilize their fields. The beneficial and salutary effects
of this practice in husbandry, makes it look as if nitrous acid and
nitrous airs were good manures, and that vegetables had the power
of decompounding them. That in short, in the œconomy of plants,
there is a process by which the septon and oxygene of these infec-
tious fluids are separated, and, while the former remains in the ve
getable, as a part of its nutriment, the surplusage of the latter, af-
ter forming gum, mucus, meal, &c. and other vegetable oxyds, flies
off through the upper surface of the leaves, in company with heat
and light, in the form of vital air.
In order to establish this conclusion, it will be necessary to show,
that vegetables contain the principle of putridity. The most rea-
dy way of coming at this will be by examining whether they con-
tain ammoniac (volatile alkali.) Ammoniac has the same radical
(septon) with nitrous acid, but the two compounds differ from
each other in this, that to form ammoniac, septon is combined
with hydrogene; whereas in the composition of nitrous acid sep-
ton is connected with oxygene. If the volatile alkali then can be
produced from plants, it will be a proof that, the radical of the ni-
trous acid (septon) is an ingredient in the vegetable structure.
Pit-coal is generally considered as a substance of vegetable origin.
In the treatment of coal, to procure tar from it, by Lord Dundon-
ald's process, a large amount of volatile alkali is obtained. That
whole class of vegetable bodies called funguses, or the toad-stool
tribe,


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tribe, yields on analysis by fire, the volatile alkali. The whole
class of the tetradynamia, to which cabbage, mustard, hore-radish,
&c. belong, are supposed to contain or to afford a large proportion
of it. The glutinous part of meal, flour, or bread-corn, yields it
also, by distillation; and indeed most plants, urged by a strong
fire, in close vessels, or when converted into soot, give out the same
alkaline product. The case of soot, which affords a good deal of
ammoniac, is very impressive, as it seems to evince the formation
of the volatile alkali, by the junction of septon with hydrogene
in high temperatures, when at the same time there is incomplete
combustion.
There is an experiment of Dr. Priestley's, which shews the ana-
logy between nitrous acid and volatile alkali. He found (Exp.
and Observat.- vol. ii. p. 43-44) that iron, which had long rust-
ed in nitrous air, gave out a strong smell of volatile alkali. In
this experiment, the iron attracts a part of its oxygene from the
nitrous air (which always contains a quantity of water) and con-
verts it into azotic gas and azotic oxyd, The iron likewise attracts
a portion of the oxygene from the water, and sets loose a quan-
tity of hydrogene gas. Meantime the metal grows rusty, or, in
other words, is converted to an oxyd. But while this goes on, or
afterwards the component ingredients of volatile alkali are evolv-
ed, and thus the azote and hydrogene combine to form ammoniac.
An experiment of Mr. Milner's is very much in point. By ex-
posing alkaline air to substances containing oxygene, in a red
heat, he produced nitrous gas, (Phil. Trans, vol. lxxix. p. 300.)
Here it seems, the hydrogene of the ammoniac quitted its connec-
tion, by reason of some more powerful attraction, and afterwards
its radical (azote) combined with the principle of acidity to form
nitrous air. We see, thus, how the azotic basis, by combining
with oxygene, forms a nitrous, or with hydrogene, an alkaline
product.
There is thus no difficulty in conceiving whence vegetables
get their azote. Nitrous acid, and some other combinations of
azote with oxygene constitute a large proportion of the fertilizing
part of street manure. The powers of vegetation are capable of
dissolving the connection between these two materials and the
oxygene evaporates, while the azote attaches itself to the plant, as
one of its nourishing materials. It has been said that volatile al-
kali exists, naturally formed, in some plants, and nitrous acid in
others; but these assertions require farther confirmation by expe-
riment. The better opinion seems to be, that they are both
formed on, or by the putrefaction and distillation of such vegeta-
ble bodies as contain their constituent parts. The nitrous acid,
I and


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and the analogous products, being commonly produced by com-
mon putrefaction, in ordinary summer heats; and the volatile al-
kali in high ranges of artificial heat, in distillation and incineration.
It seems (3 Priestley’s Exp. and Obs. p. 415) that charcoal is,
in some cases, capable of affording azotic air; but this only happens
when, after expulsion of all the air it originally contained, it has
been afterwards suffered to imbibe atmospheric air. On expel-
ling this secondary portion, there is no carbonic acid procured,
but all it azotics. Its oxygene is probably absorbed, and, as
Bancroft very ingeniously conjectures, (1 Philosophy of Perma
nent Colours, &c. p. 48) forms the black oxyd of charcoal.
It may appear like a strange idea, that nitrous acid and its va-
pours and airs, should aa as manures, and assist in fertilizing land.
It is, however, a certain fact, that this is the case; and, on the ra-
pid evaporation and absorption of these compounds when strew-
ed ever the land, can it be explained why street-manure has so
little durability, and leaves so soon the fields on which it had been
spread in a state of exhaustion. In like manner it becomes easy
of comprehension, why spots too highly manured, as well as heaps
of manure themselves, possess the fertilizing ingredient in a state
too strong and condensed to support vegetable life at all. In
order to operate well, and  produce its greatest good effects, this
manure should be tempered with common earth, and by no means
be spread too thick upon the ground. Unless this be attended to,
the manure will corrode or poison the plants it is intended to sti-
mulate and nourish.
Street dirt and dung thus contain nitrous acid. Vegetables
absorb it, decompound it, and attach its basis while they exhale
its oxygene through their leaves into the atmosphere. This ba-
sis, in common putrefaction is ready to combine with oxygene into
nitrous acid again; and in high heats to connect itself with hydro-
gene into volatile alkali.
That some extrordinary process of putrefaction went on during
the pestilential autumn of 1795, in New-York, was evident, not
only from the general luxuriance of most vegetables, but from the
production of a second crop of flowers by many plants which
commonly bloom but once in a season, particularly pinks, apple-
trees, and cherry-trees. Notwithstanding the advantages derived
to mankind from the destruction of vitiated air, and the produc-
tion of vital air, by the œconomy of plants, the police of the city
of New-York, a few years ago, caused a large number of the trees
growing throughout the streets to be cut down ! And in the
same spirit of proceeding, the committee for preventing the in-
troduction of infectious diseases, though waited upon in person, in
consequence


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consequence of information solicited by them on the subject of
contagion, during the pestilence of 1795, deemed the principles
of the present communication not worth the hearing! Is it won-
derful we are visited by plagues ?
With sentiments of esteem and respect,
I am, Sir, your very humble servant,
SAMUEL L. MITCHILL.
New-York, Feb. 20, 1796.
[NOTE E.]
The Power of Oxygene and Azote to colour Animal Substances. Ex-
tracted from " Experimental Researches concerning the Philosophy of
Permanent Colours, &c." vol. i. p. 30-32. By EDWARD BAN-
CROFT, M. D. F. R. S.
WE are at this time well acquainted with the constituent parts
of the acid of nitre: it undeniably consists of what the pneuma-
tic chymists term azote (phlogisticated or nitrous air) rendered
acid by its combination with a certain portion of oxygene, or the
basis of vital air. When the azote and the oxygene are combin-
ed in a certain proportion, the acid or compound is colourless, as
we see it in aqua fortis or nitric acid: but if this colourless acid,
in a transparent glass vessel, partly filled, be exposed to the rays of
the sun, or the light of a fire, an alteration will take place in the
proportion of its ingredients; since the light will combine with a
part of the oxygene, and cause it to become elastic and fly off, and
the azote will consequently predominate in the remainder; which,
merely in consequence of this predominance, will assume first a
yellow, then an orange, and afterwards a high vivid aurora, and
even a red colour, intensely affecting the sight. But if the glass
vessel containing the colourless nitric acid, were filled with it, no
such change of colour would take place by any degree of expo-
sure to the sun's rays or other light; because, in this case, there
would be no sufficient space or room to allow of a separation and
escape of the oxygene. When nitrous acid has been made to as-
sume the colours as before mentioned, if the glass vessel contain-
ing it be hermetically sealed and kept for some time in the dark,
the oxygene by losing its light, will lose its elasticity; and being
again re-absorbed by the nitrous acid, the latter will become co-
lourless, as before. Mr. Keir mentions an orange-coloured ni-
trous acid, which, by long keeping, became green, and afterwards
of


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of a deep blue; and Bergman says, that if, to a concentrated red
nitrous acid, one fourth part of the quantity or measure of water
be added, the colour will be changed to a fine green; or to a blue
by the addition of an equal measure of water, and that double its
quantity of water will destroy the colour. Here then we have an
example of all the various colours produced by the two species, of
air which compose our atmosphere (almost wholly) when depriv-
ed of their elasticity, and mixed in particular proportions with
more or less dilution by water.
In the same manner, colourless nitric acid, when applied to
wool silk, fur, or the skins of animals, their nails, horns, &c.
renders them all, not only yellow, but orange, and even aurora-
coloured. Mr. Berthollet thinks these changes are produced by
a kind of combustion;  but I am pursuaded they are the result of
a combination of the oxygene with the azote, which he has prov-
ed to be a constituent part of all animal substances; they being
exactly similar both in their nature and origin, to the changes of
colour produced as before mentioned in the nitrous acid. Were
these colours the effect of combustion, why are they not likewise
produced in the same manner upon linens, cottons, and vegeta-
ble substances, which contain either little or no azote, but a great
portion of the basis of charcoal, and ought therefore to be more
liable to be acted upon in the way of combustion, than animal
substances?