ETHYLENE BICHLORIDE 
AS AN 
ANAESTHETIC AGENT; 
WITH A CONSIDERATION OF ETHYLENE METHYLETHYLATE, 
ETHYLENE ETHYLATE, ETHYL NITRATE, 
AND ETHYLIDENE BICHLORIDE. 
By EDWARD T. REICHERT, MTV 
[.REPRINTED FROM THE PHILADELPHIA MEDICAL TIMES FOR MAY 7, MA Y 21, AND JUNE 4, 1881.] ETHYLENE BICHLORIDE AS AN ANAESTHETIC AGENT; 
WITH A CONSIDERATION OF ETHYLENE METHYLETHYLATE, ETHYLENE ETHYLS 
ETHYL NITRATE, AND ETHYLIDENE BICHLORIDE. 
its usual phenomena were present, antbthat 
this condition was not attended with any 
excitement of the pulse or subsequent 
headache, and when he took it himself it 
produced such a degree of irritation in the 
throat that it did not disappear for many 
hours. Snow! found it to be a powerful 
agent, but deems it unsafe. 
Although not much in the way of rec- 
ommendation can be said for this prepara- 
tion from the results of Simpson’s and 
Snow’s investigations, yet if we are to 
judge from those of Nunnelly it must be 
certain that in so far as its anaesthetic 
properties are concerned nothing more 
could be desired; and, indeed, the only 
objections urged by the two former in- 
vestigators are its irritancy and its danger- 
ousness. That Simpson laid entirely too 
much stress on the first of these objec- 
tions must be inferred, because Nunnelly 
found it very pleasant to inhale; and so 
far as my personal acquaintance with the 
drug is concerned, both in regard to its 
administration to others as well as per- 
sonally, it is certain that, while it does 
possess irritant properties, and does cause 
distress when first inhaled, the distress is 
certainly nothing like as severe as we are 
led to infer, nor is it much, if any, worse 
than that caused by the inhalation of ether; 
and as regards the dangerousness of the 
ethylene, a difference in opinion as to the 
degree of its dangerousness is also apparent. 
Still, it will be admitted that the weight of 
the evidence in its favor or disfavor rests 
with the assertion of Nunnelly, who made 
the most elaborate and detailed study, and, 
with such a decided recommendation, it 
is apparent that its reintroduction to the 
profession is but a matter of time. It 
therefore seems that the present is a fitting 
occasion for the reconsideration of this 
compound, and for a detailed study of its 
ETHYLENE BICHLORIDE, or ethene 
bichloride, or better known as “ Dutch 
Liquid,” and isomeric with the ethyli- 
dene bichloride, or ethidene dichloride, 
which has lately attracted attention through 
the investigations of the British Medical 
Association Committee, was first used by 
Simpson as an anaesthetic agent, and more 
recently by Nunnelly,* who, after making 
fourteen experiments on the lower animals 
and a number on his own students and 
patients, states that he found it in every 
way agreeable. In mammals thirty or 
forty minims were sufficient to cause com- 
plete anaesthesia in from two to five min- 
utes, and with a like quantity six out of 
seven students were rendered completely 
insensible, although a second dose of 
twenty minims was occasionally given. 
In six surgical cases he used it with perfect 
success, and later in his paper concludes 
that chloroform is in no respect superior, 
for the animals were rendered perfectly 
anaesthetized in quite as short a time, 
showed no uneasiness while passing into 
this condition, remained perfectly still 
while in it, and, in recovering, were alto- 
gether free from any unpleasant symptoms; 
and, further, that if animals were rendered 
so profoundly anaesthetized by chloroform 
as with it, they would not have recovered, 
and that although just as small a quantity 
would cause anaesthesia as would chloro- 
form, yet a much larger quantity was re- 
quired to destroy life, and hence its greater 
safety. Simpson,f who had previously 
used it, stated that when its vapor was in- 
haled it caused so much irritation in the 
throat that but few persons could endure 
inhaling it until anaesthesia was produced. 
He, however, certifies that he has seen it 
inhaled perseveringly until anaesthesia and 
* Transactions of the Provincial Medical and Surgical 
Association, xvi., 1849, P- 2°®- 
t Edinburgh Medical Journal, viii., 1848, p. 740. 
I Anesthetics. 2 
ETHYLENE BICHLORIDE 
properties as an anaesthetic agent, because 
we find the confidence in chloroform so 
universally shaken, the slowness, uncer- 
tainty, and many other practical disadvan- 
tages of ether so keenly felt, and that the 
anaesthetics recently introduced, and which 
were oftentimes lauded to the highest ten- 
sion, have miserably failed to fulfil the 
promises made for them, and have even 
added their victims to the already ghastly 
anaesthetic holocaust. Hence the profes- 
sion is eagerly searching for a compound 
which will prove to be as safe as ether and 
to possess all the advantages of chloroform; 
and, while such a stimulus exists for re- 
search and experimentation with this class 
of compounds, we must expect, even at this 
time, when the physiological laboratories 
of our institutions of medical learning are 
open for original research, and scarcely 
any investigator can plead an absence of 
facilities for vivisection, to find those who 
are so utterly reckless as to imperil the 
lives of their patients by experimenting 
on them before a proper physiological 
study has been made on the lower animals 
and the anaesthetic satisfactorily proven to 
be safe. How it is that these workers of 
death presume to be invested with the 
moral and legal right to unnecessarily 
jeopardize the lives of their patients is 
inexplicable. 
From this it will be understood that the 
object of the writer in the preparation of 
this paper was to determine by an experi- 
mental investigation on the lower animals 
as to whether or not this anaesthetic es- 
pecially, which appears so promising, is a 
safe one to use on the human being, and 
if it does possess any decidedly dangerous 
properties to point them out, so that if 
necessity or preference should ever call 
for its use we will be forearmed by being 
forewarned, and thus, anticipating certain 
dangerous results, can meet them promptly 
and efficiently. And, when it is considered 
that the degree of dangerousness of any an- 
aesthetic lies practically in its effects on the 
circulation, the amount of labor necessary 
to satisfactorily determine this point is not 
so formidable as it would at first appear. 
All anaesthetics certainly do depress the 
sensory nerves or centres, and especially 
so, the cerebral centres. It is therefore 
obvious that we cannot hope for a prepa- 
ration of this class which will not have a 
tendency to cause death by overwhelming 
certain vital portions of the nervous sys- 
tem and thus secondarily causing asphyxia 
or shock; yet the warning of asphyxia is 
generally so apparent that a fatal result 
can be avoided. But, on the other hand, 
where we have a compound which exerts 
an independent depressant action on the 
heart besides, we have a double danger to 
deal with ; and that the large majority of 
deaths following the use of chloroform and 
bichloride of methylene were due either 
to a paralysis of the heart alone or to sec- 
ondary results because of such a depression, 
by which the already depressed nervous 
centres are further depressed or paralyzed 
on account of an inefficient supply of blood, 
must be apparent; and, while it is prac- 
tically out of the question to even hope 
for an anaesthetic which will not cause 
death by paralyzing the nervous centres 
and thus causing shock or asphyxia, our 
one hope still lies in the effort of avoiding 
those preparations which decidedly depress 
the heart and which past experience has 
taught to be invariably dangerous, and 
of obtaining a compound devoid of this 
dangerous quality. 
In the present investigation three modes 
of giving the ethylene bichloride were em- 
ployed : ist, by inhalation by means of a 
Woulfe bottle, by which method the air 
which the animal inhaled was compelled 
to pass through the bottle having in the 
bottom either the ethylene alone or numer- 
ous pieces of sponge saturated with it, the 
tube for the entrance of the air running 
almost to the bottom of the bottle, and 
the exit-tube being very short and merely 
extending to the bottom of the cork, so 
that the air which the animal breathed was 
always more or less saturated with the 
ether; 2d, by inhalation from a muslin 
cone held closely over the tracheal tube 
or nostrils; 3d, by intravenous injection. 
General Action.—In normal animals, 
and when administered by the use of the 
usual muslin or linen cone, there are, 
as with most anaesthetics, three distinct 
stages,— excitant, anaesthesia, and pro- 
found narcosis. With the ethylene we 
have struggles, general symptoms of intox- 
ication, and blunted sensibility, a quick- 
ened pulse and accelerated respirations. 
Consciousness, sensibility, voluntary mo- 
tion, and reflex action become rapidly 
annulled; and the animal lies perfectly 
relaxed, and is thoroughly anaesthetized. 
If the inhalation is persisted in, profound 
narcosis rapidly supervenes, the pulse and AS AN A NAES THE TIC AGENT, ETC. 
3 
respirations fail, and death ensues from a 
failure of the latter. The pupils may at 
first be dilated, but are afterwards con- 
tracted, and the further the anesthetiza- 
tion is pushed the more fully they become 
so, unless it be in the last of the profound 
narcosis stages, when, preceding death, 
they have been observed occasionally to 
become dilated. Sensibility is invariably 
lost before motion, and I have almost 
unexceptionally seen muscular movements 
occur—not infrequently like clonic con- 
vulsions—after the complete abolition of 
orbital reflexes. It also appeared that the 
cerebral functions were more seriously af- 
fected before other parts of the system. 
Early in my experiments I learned that 
in order to know whether an animal was 
completely anaesthetized it was not neces- 
sary to consult the conjunctiva, but merely 
to watch the respirations, for just so soon as 
they became very frequent the animal was 
either anesthetized or so near and rapidly 
approaching that condition that the inhaler 
could be removed and tbe operation proceeded 
with. If after the second stage is very pro- 
nounced the administration of the ethylene 
be continued, the animal invariably dies 
from a failure of the respiration, and never 
in a single mstance could I induce death by 
a stoppage of the heart by the inhalation of 
the vapor, no matter how concentrated the 
vapor was. 
The dose required to produce anaesthesia 
was about the same as chloroform, for the 
difference was so slight as to be unnotice- 
able. 
The Pulse.—The pulse-rate is invariably 
and decidedly increased, even in the most 
profound narcosis, and not until near death 
does it approach or fall below the normal, as 
the following records will show, which have 
been copied from kymographion tracings: 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
4-35 
48 
Anesthetization complete. 
Maximum increase n, or 
*9 per cent. 
Exp. II. [October 6, 1880).—Rabbit. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
I. 
45 
Commenced inhalation as 
previously on an animal sim- 
ilarly rendered immovable. 
.25 
46 
•45 
45 
2.05 
47 
.25 
48 
•45 
58 
3-05 
53 
Animal anaesthetized. 
.25 
55 
•45 
61 
4.05 
54 
•25 
47 
•45 
54 
Maximum rise 16, or 35 
5.05 
52 
per cent. 
Exp. III. (October 7, 1880).—Rabbit. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
I. 
.05 
33 
Commenced inhalation 
with the use of the cone of 
muslin, it being held over 
the tracheal tube. 
.20 
37 
2. 
38 
40 
45 
3-20 
42 
4- 
Added more ethylene to 
inhaler. 
.40 
48 
5.20 
48 
6. 
47 
Respirations ceased. 
.40 
47 
7.20 
45 
8. 
47 
Respirations commenced, 
but are shallow. 
.40 
44 
9- 
46 
Respirations became slower 
and deeper, and finally 
ceased. The heart contin- 
ued beating for at least four 
minutes, and gradually 
ceased. 
Maximum increase 15, or 
45 per cent. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
I. 
•°5 
37 
Commenced inhalation by 
Woulfe bottle. The animal 
was previously curarized, and 
artificial respiration was re- 
sorted to, the apparatus being 
connected with the Woulfe 
bottle. 
•15 
37 
•55 
38 
2-35 
46 
3-i5 
48 
•55 
45 
Exp. I. 1880).—Rabbit. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
I. 
•03 
36 
Commenced inhalation by 
the use of the linen cone. 
.07 
■32 
39 
42 
39 
Arterial pressure falling 
slightly. 
Exp. IV. (October 9, 1880).—Rabbit. 4 
ETHYLENE BICHLORIDE 
Time. 
Pulse in 
Remarks. 
M. Sec. 
ten sec. 
2.0 7 
49 
Arterial pressure rising 
slightly. 
.27 
46 
The arterial pressure slowly 
rising; the pulse-curves are 
about one-third the height of 
the normal; the respirations 
are scarcely perceptible. 
•47 
46 
Arterial pressure a little 
lowered, and equalling about 
seven-eighths of the normal. 
3-°7 
48 
Arterial pressure rising 
slightly. 
.27 
46 
•47 
46 
Arterial pressure falling, 
and equalling about three- 
fourths of the normal. 
4.07 
48 
.2 7 
45 
Arterial pressure falling 
slightly. 
.47 
5° 
5.07 
54 
•47 
45 
6.07 
46 
Arterial pressure falling 
slightly. 
•2 7 
48 
•47 
44 
Arterial pressure falling, 
and equalling about five- 
sevenths of the normal. 
7- 
Added more ethylene to 
inhaler. 
•07 
46 
10. 
45 
.20 
46 
.40 
46 
11. 
46 
.20 
45 
•55 
46 
Added more ethylene to 
inhaler. 
•58 
12.15 
46 
•35 
46 
•55 
46 
I3*I5 
46 
.40 
45 
15. 
46 
17. 
43 
20. 
43 
.20 
43 
•3° 
Added more ethylene to 
inhaler. 
.40 
45 
21. 
5° 
.20 
48 
22.15 
45 
•35 
42 
•55 
47 
23-15 
45 
•35 
43 
Arterial pressure one-half 
of the normal. 
24.15 
43 
25-35 
40 
26.05 
42 
•25 
47 
•45 
42 
27.05 
43 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
27.25 
42 
Arterial pressure three- 
eighths of the normal. 
Maximum increase 18, or 
50 per cent. 
At the time of the conclusion of this 
record the pulse-curves had become so 
small as to be indistinguishable, and the 
tracing made by the marker was but a 
mere streak. When the fingers were placed 
on the chest of the animal, only a faint 
movement of the heart was perceptible, 
and the action of the viscus was more like 
tremors than distinct pulsations. The 
respirations at this time, if they were 
present at all, were so shallow as to be 
indiscernible. 
The animal was allowed to remain un- 
disturbed for about two minutes, and when 
a further examination was made the move- 
ments of the heart were found to be so 
feeble as to be almost inappreciable, and 
not the slightest respiratory movements 
were detected. The heart still possessing 
some vitality, it was thought that by at- 
taching the artificial respiration-apparatus 
to the tracheal tube the respirations might 
possibly be restored and the moribund 
animal revivified. This was done, and 
after the lapse of two minutes not the 
least evidences of respiratory movements 
or of a restoration of the vitality of the 
almost paralyzed heart were present, and, 
as all signs of life save the almost imper- 
ceptible movements of the heart were 
gone, the animal was given up as being of 
no further use, and the artificial respiration- 
apparatus detached. In a few moments, 
however, it occurred to the writer that as 
this drug was probably both a cardiac and 
a respiratory depressant in toxic amounts, 
and that, as previously stated, death in- 
variably occurred from a paralysis of the 
respiratory movements, we would have an 
invaluable antidote and revivifier in the 
nitrites if what the writer asserted in a 
recent article* was true, which was to the 
effect that the nitrites, in small or mod- 
erate doses, were powerful respiratory and 
cardiac stimulants. Although the long- 
continued absence of respiratory move- 
ments and the almost complete extinction 
of all the vital functions were points de- 
cidedly against a successful result of such 
an experiment, yet, while a negative result 
* American Journal of the Medical Sciences, July, 1880, 
p. 158. .AS AN ANESTHETIC AGENT, ETC. 
5 
would not therefore materially disprove 
the above assertion, the opposite result 
would be strong, if not almost conclusive, 
testimony in its favor. The amyl nitrite 
was quickly obtained, and in a few mo- 
ments several drops (probably five) were 
quickly injected into the tracheal tube, 
and the artificial respiration-apparatus 
again attached, so that the vapor of the 
nitrite would be forced into the lungs 
and thus become absorbed. In a few 
moments, to my intense gratification, the 
almost paralyzed heart seemed invested 
with a new life, and every moment its lost 
powers were being rapidly restored, the 
pulse-curves gradually increasing in height 
and volume, and in a less time than it 
takes to pen these notes were equal to the 
normal, and the heart was pulsating at the 
rate of forty beats in ten seconds, or four 
pulsations above the normal. The respi- 
rations did not recur for at least two min- 
utes, and were then both shallow and slow, 
but in a few moments they had become so 
rapidly restored that they occurred at the 
rate of thirty-six per minute; two minutes 
later they were twenty-two per minute; at 
the seventh minute they were again thirty- 
six and the pulse in ten seconds forty- 
two ; at the eleventh minute they were 
forty-two; at the fifteenth minute they 
were fifty-one and the pulse in ten seconds 
forty-two. Several drops of the nitrite 
were twice injected into the tracheal tube 
since the first recurrence of respiratory 
movements. 
At the commencement of the inhalation 
of the amyl nitrite the arterial pressure 
was about one-third of the normal, and at 
the end of fifteen minutes it had not ma- 
terially changed either one way or the 
other, although slightly lowered, which 
was quite contrary to what might be ex- 
pected, since there was an augmentation 
of the frequency as well as of the force 
of the heart; but when it is remembered 
that the nitrites cause such intense vaso- 
motor dilatation, and that, notwithstand- 
ing the fact of their being decided cardiac 
stimulants, they cause a decided lowering 
of the blood-pressure in normal animals, 
the explanation of this apparent anomaly 
is evident. That we have in the nitrites 
an invaluable class of physiological anti- 
dotes for this compound is so clearly proven 
by the above as to need no further com- 
ment. 
To return to the results of the preceding 
four experiments made on normal animals. 
It will be noticed that a decided increase 
in the pulse-rate invariably occurs, and 
that this increase continues far above the 
normal until immediately before death 
(Exp. III.), when it gradually failed, the 
increase being, respectively, 29, 35, 45, 
and 50 per cent., and the average about 
40 per cent. The pulse-curves were di- 
minished (Exp. IV.), and the arterial 
pressure decidedly lowered. In order to 
determine the modus operandi of this in- 
creased pulse-rate, it was first sought to de- 
cide whether the vagi apparatus was con- 
cerned : so the following experiment was 
made, in which both vagi nerves were 
severed, a tracheal tube was inserted, and 
the ethylene given by inhalation from a 
muslin cone, with the following result: 
Exp. V. (October 13, 1880).—Rabbit. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
Cut the pneumogastric 
nerves. 
I. 
35 
•03 
Commenced inhalation. 
.IO 
35 ) 
Arterial pressure reduced 
.30 
34 
about one-tenth of the nor- 
.50 
34 j 
mal. 
2.10 
37 
Pressure rose since 1.50, 
and is now about one-tenth 
of the normal above it. The 
respirations had now become 
very frequent, and for one 
minute the pulse-curves were 
not traced, only the respira- 
tory curves. 
The respirations, which 
were normally seven in 
twenty seconds, are now in- 
creased to thirty-seven. 
The arterial pressure falls 
gradually until 3.15, when it 
reaches one-tenth below the 
normal; it then arose slightly, 
followed by a fall to the former 
point. 
3.20 
42 
40 
42 
4- 
42 
Pressure one-tenth below 
•35 
•55 
5-i5 
42 
42 
50 
- the normal, and gradually 
declining. 
•35 
52 
■55 
53 
46 
6.30 
.50 
45 
7.10 
45 
Pressure one-fourth below 
•3° 
44 
the normal. 
.50 
45 
8.25 
46 
•45 
45 6 
ETHYLENE BICHLORIDE 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
9-°5 
46 
.25 
46 
Pressure about five-twelfths 
•45 
47 
below the normal. 
13- 
45 
O O 
(N CO 
46 
Added more ethylene to 
inhaler. 
.40 
44 
14. 
45 
.20 
43 
•32 
Respirations ceased. 
.40 
38 
*5- 
29 
•35 
26 
16.15 
27 
•55 
28 
17.25 
26 
•45 
27 
Since the fifteenth minute 
the pressure has gradually 
declined, and is now about 
one-fourth of the normal. 
•55 
The cardiac pulsations are 
so feeble as to be impercepti- 
ble, and at 18.25 the pressure 
fell to zero. 
Maximum rise 18, or 51 
per cent. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
3- 
34 
.20 
36 
.40 
40 
4.05 
40 
5- 
37 
7- 
24 
9- 
21 
The pulse continues failing. 
Exp. VII. {October 14, 1880).—Rabbit. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
I. 
39 
.IO 
Commenced inhalation by 
Woulfe bottle. 
.20 
32 
.40 
3° 
Pressure has fallen one-half 
of the normal, and is still de- 
clining. 
2.15 
35 
•35 
27 
•55 
20 
3-i5 
20 
.40 
34 
4- 
34 
.20 
34 
Pressure about one-third of 
the normal. 
It will be noticed that the result in this 
last experiment is identical with those 
made on normal animals, with the excep- 
tion that a rise of the arterial pressure 
occurred which went above the normal. 
The pulse-rate was increased 51 per cent., 
which was as much as the greatest increase 
in any of the preceding observations, and, 
although the pulse-curves were not referred 
to in the preceding remarks, yet the same 
diminution of their size was apparent. It 
is therefore evident that the increased 
pulse-rate occurs independently of the 
pneumogastric nerves, and that it must be 
due either to a direct cardiac action or to 
a stimulation of the accelerator nerves. 
The determination of this point is satis- 
factorily accomplished by making, in the 
same animal, a combined section of both 
the cervical spinal cord and vagi nerves 
(in the section of the former the acceler- 
ator nerves are severed before their exit 
from the cord). This operation has been 
done in the two following experiments: 
These results being directly the reverse 
of what has hitherto been recorded, it is 
very evident that the increased pulse-rate 
such as occurs in normal animals is de- 
pendent upon a stimulation of the accel- 
erator nerves. Were it dependent upon 
the heart, the increase would still be ap- 
parent in animals operated on like the 
above, but which is not the result here; 
and it is an interesting fact to note that 
instead of the increase we have a diminu- 
tion below the normal from the first; and 
the fact that the heart is isolated from the 
reception of any centric influences shows 
that the decline of the pulse is due to a 
depression of the heart itself. The con- 
sentaneous occurrence of a diminished 
pulse-rate, diminished pulse-curves, and 
diminution of arterial pressure decidedly 
indicates cardiac depression, and all three 
are undoubtedly due to this, unless it be 
that the diminution of arterial pressure 
may possibly, to a considerable extent, be 
due to vaso-motor dilatation. 
A decided increase of the pulse-rate 
occurring in normal animals or in those 
having the accelerator nerves intact, and 
a diminution occurring in those in which 
the nervous connections of the heart were 
severed, is an exceedingly interesting point, 
and shows that the heart in normal ani- 
mals is affected consentaneously in a dual 
manner, and that these two forces are in 
Exp. VI. (October 12, 1880).—Rabbit. 
Time. 
Pulse in 
Remarks. 
M. Sec. 
ten sec. 
I. 
41 
.IO 
Commenced inhalation by 
Woulfe bottle. 
•3° 
38 
.50 
38 
2.40 
35 AS AN ANAESTHETIC AGENT, ETC. 
7 
constant antagonism, the one tending to 
cause an increase through a stimulation of 
the accelerator nerves, and the other a 
diminution by a direct paralyzant action 
on the heart. And it is evident that the 
effects of the stimulation of the accelerator 
nerves are more intense than those of the 
direct action on the heart: hence we have 
the increase. In two dogs, one in which 
the fibres of the accelerator nerves were 
cut a little below the medulla oblongata, 
and to which intravenous injections were 
given, the results, as the following records 
show, are confirmatory of what has already 
been stated. 
The Effect on the Arterial Pressure.— 
When the ethylene is given by inhalation 
and by the modes already described, the 
arterial tension is but little affected during 
the first few minutes, unless the vapor be 
given in a very concentrated condition 
(Exp. X., XII., and XIII.), and then 
there is a very rapid decline, equalling 
nearly one-third of the normal, which is 
followed by a rise of half this amount, 
and then by a subsequent fall. In experi- 
ments where the air was heavily laden with 
the vapor (Exp. XIII.) essentially the same 
result occurred, but in the others, where 
the vapor was given more diluted, the fall 
of pressure is not nearly so marked, and 
the subsequent rise may nearly reach or 
even go above the normal. In Exp. XI., 
XII. and XIII. the animals were cura- 
rized to obviate any complications of the 
respirations, and the artificial respiratory 
apparatus, of course, employed. In Exp. 
X. the cone was kept almost saturated 
with the ethylene, and in Exp. XII. and 
XIII. sponges were placed in the bottom 
of the bottle, which were kept continually 
moistened with the liquid, and the air 
being driven through them, thus necessi- 
tating the absorption of considerable of 
the anaesthetic by the current of air. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
I. 
l6 
.IO 
Injected thirty minims in- 
travenously. 
.22 
The blood-pressure fell rap- 
idly to one-half of the normal; 
deep respirations and strug- 
gles sent it up to normal 
twelve seconds later; it then 
commenced to decline, reach- 
ing one-half of the normal at 
thirteen seconds later; and 
then commenced to rise 
gradually, reaching to within 
one-eighth of the normal at 
the fourth minute. 
40 
23 
2.20 
23 
.40 
23 
3- 
25 
.20 
25 
.40 
23 
4.20 
22 
.40 
23 
5- 
22 
.20 
21 
.40 
19 
6. 
20 
.20 
x9 
Maximum increase g, or 56 
.40 
20 
per cent. 
Exp. IX.—Dog. 
Time. 
M. Sec. 
Pulse in 
ten sec. 
Remarks. 
I. 
25 
Cut the spinal cord a little 
below the medulla. 
.05 
Injected thirty minims in- 
travenously. 
.20 
25 
2. 
23 
.IO 
22 
.20 
23 
•30 
21 
4- 
20 
.20 
21 
•45 
22 
Exp. VIII.—Dog. 
Exp. X.—Rabbit. 
Time. 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
I. 
56 
Commenced inhalation 
from a cone, which was kept 
wet throughout the experi- 
ment. 
•°7 
52 
•32 
39 
.42 
32 
2.07 
42 
.27 
46 
Respirations almost imper- 
ceptible. 
•47 
42 
3-°7 
40 
.27 
46 
•47 
45 
4.07 
45 
.27 
44 
•47 
4i 
5.07 
4i 
•47 
45 
6.07 
44 
•47 
40 
7.07 
42 
Added more ethylene to 
inhaler. 
10.20 
42 
11.20 
•55 
42 
Added more ethylene to 
inhaler. ETHYLENE BICHLORIDE 
Time, 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
12.15 
41 
•55 
39 
13.40 
38 
17- 
37 
20. 
36 
•30 
Added more ethylene to 
inhaler. 
21. 
33 
23- 
3i 
• 
24. 
3i 
25. 
28 
26. 
28 
27.25 
to 
No pulse-curves are distin- 
guishable on the tracing. 
Time. 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
1.25 
44 
•45 
46 
• 
2.05 
37 
.25 
3i 
•45 
43 
3-05 
45 
Animal completely anaes- 
thetized. 
.25 
46 
•45 
47 
4.05 
53 
.25 
5o 
•45 
45 
5-°5 
4i 
• 
.25 
40 
•45 
37 
6.05 
33 
•45 
3i 
7-45 
3i 
945 
30 
10.05 
29 
Added ethylene. 
•45 
29 
11.25 
28 
Added ethylene. 
12.05 
26 
.25 
23 
•45 
22 
13-45 
20 
14.25 
18 
15.05 
17 
•45 
15 
No pulse. 
Exp. XI.—Rabbit. 
Time. 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
Animal curarized. 
I. 
66 
Commenced inhalation by 
means of the Woulfe bottle, 
in the bottom of which was 
placed about a drachm of 
ethylene. 
.12 
64 
.20 
64 
2.20 
63 
.40 
63 
3- 
61 
.20 
61 
4- 
61 
.40 
56 
Animal completely anaes- 
thetized. 
6.40 
56 
7- 
60 
.40 
60 
8. 
62 
.40 
Dropped thirty minims 
ethylene in bottle. 
9- 
58 
.20 
60 
11.20 
56 
•3° 
Dropped thirty minims 
ethylene in bottle. 
.40 
57 
12. 
58 
.10 
Dropped thirty minims 
ethylene in bottle. 
.40 
53 
13- 
48 
.10 
Dropped thirty minims 
ethylene in bottle. 
.20 
47 
, 
.40 
5i 
14. 
45 
Time. 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
I. 
54 
• IO 
Woulfe bottle used in which 
sponges were placed wet with 
the ethylene. 
.20 
54 
•45 
52 
2.40 
48 
3.20 
44 
.40 
48 
Added more ethylene. 
4- 
48 
.40 
49 
5- 
47 
.20 
44 
.40 
50 
6. 
52 
.20 
48 
.40 
48 
7- 
44 
.20 
3i 
8. 
25 
.40 
32 
9- 
32 
.20 
25 
10. 
19 
.40 
17 
11. 
15 
Exp. XIII.—Rabbit. 
Exp. XII.—Rabbit. 
Time. Pressure. 
M. Sec. Mm. 
Remarks. 
i. 45 
.05 
Commenced inhalation, 
using the Woulfe bottle as 
before. 
From these results it will be seen that 
the most pronounced effect of the ethylene 
on the blood-pressure when given by con- AS AN ANESTHETIC AGENT, ETC. 
9 
tinuous inhalation, whether in a dilute or 
concentrated form, is to produce a dimi- 
nution to zero, but which is transiently 
interrupted by a rise towards the normal, 
which is various in extent and may go 
even above it (Exp. XII.). As these 
changes in the pressure occur in curarized 
animals, any effect which altered respira- 
tions or muscular movements might have 
is obviated by this toxic condition; but 
as this diminution of pressure is accom- 
panied by a frequent pulse and diminished 
pulse-curves, which latter has already been 
pointed out to be due to a depressed con- 
dition of the cardiac, power, it is at once 
indicated that the fall of pressure is cardiac 
in its origin. However, several experi- 
ments made on animals with cut pneumo- 
gastrics gave results identical with those 
already recorded on normal animals. It 
therefore remained but to show whether 
the heart or vaso-motor system (or both) 
was the cause of the above results. Con- 
sequently, the heart being the most prob- 
able agency, experiments were made on 
animals in which the pneumogastric nerves 
and the cervical spinal cord were cut, which 
would necessarily sever all nervous connec- 
tion with the heart, and whatever results 
would then follow would evidently be due 
to a direct cardiac action or to one on the 
peripheral vaso-motor mechanism. 
with the major part of the vascular capil- 
laries, and practically (for our purposes) 
annihilating the vaso-motor peripheries, 
while the section of the cord practically 
destroys the vaso-motor centres. 
Exp. XV 
Time. 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
I. 
53 
Cut cord in upper cervical 
region ; cut vagi and ligated 
thoracic aorta. 
•°5 
Inhalation by Woulfe bot- 
tle. 
•15 
55 
.25 
48 
•35 
34 
•45 
28 
2.05 
23 
.25 
•45 
25 
24 
/ 05 s' 
3-°5 
21 
[ ( 
.25 
•45 
20 
18 
4.25 
•45 
5.05 
16 
15 
14 
6.25 
13 
7.25 
12 
8.25 
11 
9- 
10 
10. 
8 
No pulse traced. 
The fall of pressure being still as marked 
in this last experiment, it must be concluded 
that the depression of the cardiac power 
is the cause of it, and, in further corrobo- 
ration of this, it has been found that in 
animals whose thoracic cavity was opened 
the direct application of the ethylene to 
the heart caused its slowing or immediate 
arrest, and, further, that in animals slowly 
poisoned an autopsy revealed the heart ar- 
rested in diastole. It is probable, though, 
that the transient rise of pressure which 
interrupts the fall in normal animals is 
vaso-motor and both centric and peripheral 
in its origin, because it did not occur in 
either of the last two experiments; yet it 
was well marked in an experiment made 
on an animal with a cut cervical cord 
which has not been recorded in this paper. 
In looking over the above series of ex- 
periments it is interesting to note that, 
although the drug is a direct and decided 
cardiac depressant, this organ is capable 
of bearing a considerable amount of de- 
pression before its complete paralysis, and, 
as was stated early in the paper, the respi- 
rations are always the first to succumb, 
and death is caused in this way. And it 
Exp. XIV—Rabbit. 
Time. 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
I. 
21 
Cut the pneumogastrics and 
cervical spinal cord. 
.05 
Inhalation by Woulfe bot- 
tle. 
■15 
*9 
.25 
21 
•45 
17 
2.05 
18 
.25 
17 
•45 
15 
3-°5 
H 
•25 
13 
•45 
12 
4-45 
12 
5.25 
12 
No pulse traced. 
The fall of pressure still occurring, the 
following experiment was made to deter- 
mine if the vaso-motor peripheries were 
concerned, and, in order to accomplish 
this object, the pneumogastric nerves and 
cervical spinal cord were severed and the 
thoracic aorta ligated, this latter operation 
cutting off communication of the blood ETHYLENE BICHLORIDE 
was further found that if after the complete 
cessation of the respirations the artificial 
respiration-apparatus was attached and air 
laden with the ethylene vapor driven into 
the lungs the heart would still continue to 
pulsate for some minutes. After the blood- 
pressure had fallen almost to zero and the 
heart-beats could no longer be traced on 
the drum, yet when the thorax was opened 
the organ was still feebly pulsating, and 
continued so for several minutes. This 
fact is certainly an interesting one to re- 
member., for in case of accident during 
its use, the absence of pulsations at the 
wrist would not be so serious as it other- 
wise would, and by reference to the text 
immediately following Exp. IV. the in- 
valuable services to be looked for from the 
amyl nitrite cannot be overestimated. 
And in those cases where a sudden arrest 
of the respiratory movements occurs, the 
same good services can be expected, for it 
is evident, from the results of some of the 
preceding experiments, that the ethylene 
acts primarily as an excitant and secon- 
darily as a depressant to the respiratory 
centres. That the respiratory movements 
must be arrested by centric paralysis is 
evident from the results of the experiment 
just quoted, for if it were due to a paralysis 
of the respiratory muscles, or of the ner- 
vous communication failing to convey the 
impulses from the centres, scarcely such a 
rapid recovery of full, regular, almost nor- 
mal respirations could occur, since the ni- 
trite acts as a depressant to both the motor 
portions of the cord and nerves and vol- 
untary muscles. Yet the recovered respi- 
rations could be attributed to some extent, 
probably, to a greater supply of blood to 
the anaemic respiratory centres, for the 
reason that the increased force and fre- 
quency of the heart must have been the 
cause of driving considerably more blood 
through the centres, even if the blood- 
pressure was not increased and the respi- 
ratory centres were thus also indirectly 
stimulated by the nitrite. It is very evi- 
dent that in the nitrites we have both 
respiratory and cardiac stimulants, and 
therefore a double physiological antidote 
by acting similarly upon the depressed 
heart and respiratory centres; and the im- 
portance of this knowledge cannot be too 
deeply impressed on the minds of those 
who will hereafter make use of this prep- 
aration. 
As an anaesthetic for general surgical use 
it is undoubtedly superior to any yet intro- 
duced, with the exception of its isomeric 
compound ethylidene chloride and ether, 
and is inferior to the latter in but the 
single point regarding the relative degree 
of safety; and, while it in all probability 
is equal to chloroform in strength, prompt- 
ness, and permanency of effects, it is fully 
as much superior to it in the point of safety 
as it is inferior to ether. This last is 
very evident by referring to the records 
of the experiments made on the arterial 
pressure, where it will be seen that the 
diminution of the arterial tension is that 
of a gradual decline, decidedly unlike that 
caused by the slow administration of chlo- 
roform, because of the absence of those 
wide and remarkable variations which oc- 
cur, especially before complete anaestheti- 
zation. Also, when the vapor is given in 
a state of concentration by saturating a 
muslin cone with the liquid and placing it 
directly over the tracheal tube, as in Exp. 
X., although we have a decided fall of 
pressure, yet it does not immediately de- 
cline to zero, but consumes twenty-seven 
minutes in reaching within as many milli- 
metres of it. Now let us turn to a similar 
experiment made with chloroform, and the 
difference in the results is strikingly great: 
Time. 
M. Sec. 
Pressure. 
Mm. 
Remarks. 
I. 
59 
Gave thirty minims of chlo- 
roform by inhalation from a 
muslin cone held over the 
tracheal tube. 
.IO 
58 
.20 
57 
•30 
52 
•45 
48 
.50 
34 
2.00 
18 
.10 
12 
No pulse. 
Exp. XVI.—Rabbit. 
The diverse and interesting results of 
these parallel experiments are so valuable 
as scarcely to be overestimated in a com- 
parison of the relative safety of the two 
compounds, as the pulse in the ethylene ex- 
periment could be detected on the tracing 
for over twenty-five minutes, notwithstand- 
ing that the animal was continuously in- 
haling the vapor during the whole of this 
time, while in the chloroform experiment 
but a single dose was placed on the in- 
haler, the pulse-curves rapidly diminished 
in size, and the pressure fell to twelve AS AN ANESTHETIC AGENT, ETC. 
11 
millimetres in a little over two minutes, 
and the pulse was extinct. 
It needs no further argument to prove 
that this article (or, probably, ethydene 
chloride) should replace chloroform in 
such cases where ether cannot be used; 
but, as it is inflammable, care must be 
exercised in its use at night, and, as it is 
a cardiac and respiratory depressant (in 
toxic amounts), the same cautions should 
be observed in its use, and never should 
it be employed, if possible, without amyl 
nitrite at hand. 
Before concluding, I take pleasure in 
expressing my indebtedness to Mr. Edward 
Hance (of the firm of Hance Brothers & 
White, Manufacturing Chemists, Philadel- 
phia) for the presentation of this valuable 
ether for the purpose to which it was de- 
voted. It is almost unnecessary to state 
that particular care was exercised in the 
manufacture of this specimen to have it 
pure. 
Ethylene Ethylate and Ethylene Methyl- 
ethylate were experimented with, and, 
although each of them possessed some 
slight anaesthetic powers, they were so 
feeble in this respect and caused such dis- 
tress in breathing that they were aban- 
doned as useless. 
Ethyl Nitrate was used by Simpson,* 
who found it easy and pleasant to inhale, 
and to possess very rapid and powerful 
anaesthetic properties, and that small quan- 
tities, such as fifty or sixty drops, sprinkled 
on a handkerchief produced insensibility 
after a few inspirations. Shortly after, 
Nunnellyf stated that it possessed not 
much, if any, anaesthetic power; and my 
own experiments confirm this, as the fol- 
lowing result will show: 
“ Rabbit.—Time, 12.32. Added one drachm 
to inhaler; struggles; .33, breathing 
deeper and slightly faster; .34, no change; 
.35, added a second drachm to inhaler; .35 
respirations again temporarily increased; 
•37a. orbital reflexes slightly diminished (?) ; 
.39, added a third drachm to inhaler; .40, 
respirations increased ; .43, animal not anaes- 
thetized, but somewhat drowsy, and, although 
the inhalation was continued for several min- 
utes, no anaesthesia was produced.” 
Ethidene Dichloride, Ethylidene Dichlo- 
ride, or Ethylidene Bichloride (C2H4C12), 
which is isomeric with the ethylene bi- 
chloride, has of late attracted attention 
through the researches of the British Anaes- 
thetic Committee,| who found that the 
exposed heart of the frog, in a glass jar 
containing an atmosphere impregnated 
with this vapor, continued beating slowly 
and regularly throughout the experiment, 
which lasted, in several cases, for twenty 
and twenty-six minutes respectively, al- 
though the animals were anaesthetized in 
from four to five minutes. In rabbits in 
which the thorax was opened and artificial 
respiration maintained, the cardiac con- 
tractions continued vigorous throughout 
the observations, which continued, in one 
instance, for forty minutes. Dogs were 
anaesthetized in from two to three minutes, 
and were kept fully anaesthetized for half 
an hour without the slightest failure of the 
respiration or heart. In experiments with 
the thorax opened and heart exposed (arti- 
ficial respiration being kept up) no failure 
of the heart’s action was observed, although 
the air passing into the lungs was saturated 
with the vapor. They further state that, 
practically, the animal can live for a pro- 
longed period in a state of complete an- 
aesthesia under the influence of the ethi- 
dene dichloride, while it dies in a short 
time under chloroform. And in six cases 
in which it was used§ they concluded that 
no injurious effects on the respiratory 
mechanism occur; that the pulse is low- 
ered in frequency, but increased in volume, 
and in the deepest anaesthesia it was steady, 
regular, full, and compressible; that no 
failure of cardiac action was present, as 
they were led to anticipate in their ex- 
periments on animals; that there was 
never blueness of the lips or pallor of the 
countenance; and, lastly, that the anaes- 
thetic “presents all the advantages of ether 
without any of its disadvantages.” In a 
more recent contribution|| it is asserted 
that the arterial pressure gradually but 
slowly fell, and under repeated doses 
reached a minimum of twenty millimetres, 
and after prolonged and constant use was 
gradually brought down to seven milli- 
metres. 
used it in six experiments on man, 
and to his satisfaction, and found that when 
the patients were fully anaesthetized the 
breathing became spasmodic and shallow, 
* Edinburgh Medical Journal, 1848, p. 741. 
+ Proceedings of the Provincial Medical and Surgical 
Association, 1849. 
t British Medical Journal, 1879, vol. i. p. 1. 
| Loc. cit., p. 109. || Loc. cit., p. 921. 
London Medical Times and Gazette, 1879, vol. i. p. 62. ETHYLENE BICHLORIDE AS AN ANESTHETIC AGENT 
the pulse lowered, but fuller and more 
compressible, and all of them presented the 
appearance of a strong cardiac stimulant. 
In two cases there was a rise in the pulse- 
rate, followed by a fall, and in a third 
case the pulse fell from ninety to eighty. 
The doses used varied from a drachm to a 
drachm and a half. More recently Reeve* 
has experimented with it, and his results 
“show a diminution of arterial pressure, 
not as occurs when chloroform is used, but, 
unlike it, it does not advance to complete 
extinction, nor are there such wide varia- 
tions in effects at different times in the 
same animal as in the case of chloroform. 
. . . Snow believes that it will not be 
liable to cause sudden death, as chloroform 
sometimes does. In sixteen cases it did not 
cause nausea or vomiting, although food 
had recently been taken in several of them. ’ ’ 
Steffenf reiterates Snow’s belief. 
In making the above quotations the 
writer’s object is threefold: first, to give 
sufficient detail, so that a just comparison 
can be made with the action of its sister 
compound, the ethylene bichloride, which 
the British committee stated to cause 
severe convulsions and no anaesthesia up 
to that time, while the ethidene dichlo- 
ride promised to be “an excellent an- 
aesthetic;” second, to call attention to 
the fact that it does cause a decided low- 
ering of the arterial pressure, and, there- 
fore, cannot “possess all the advantages 
of ether;” third, that a death has already 
resulted from its use.| It is probable that, 
while this anaesthetic is undoubtedly safer 
than chloroform and certainly more dan- 
gerous than ether, it bears a position of 
relative safety and power similar to that of 
its sister compound, the ethylene bichlo- 
ride.! 
J Kappeler, Part XX., German Surgery, by Billroth and 
Luecke; quoted by Reeve, American Journal of the Medical 
Sciences, July, 1880, p. 216. 
§ Another death from its use has been reported (British 
Medical Journal, May 29, 1880), and also several other cases 
in which alarming symptoms ensued. 
* Chicago Medical and Surgical Examiner, June, 1880; 
quoted in New Remedies, 1880, p. 334. 
f Binz’s Evidences of Therapeutics, p. 39.