<\ STrm* 
OF THE 
Influence of Chloroform 
UPON THE 
RESPIRATION AND CIRCULATION. 
A CONTRIBUTION FROM THE LABORATORY OF EXPERIMEN- 
TAL THERAPEUTICS OF THE JEFFERSON MEDICAL 
COLLEGE OF PHILADELPHIA. 
being a Report to surgeon lieutenant-colonel edward lawrie and to 
THE GOVERNMENT OF HIS HIGHNESS THE NIZAM OF HYDERABAD. 
BY 
H. A. HARE, M.D., 
» 
PROFESSOR OF THERAPEUTICS AND MATERIA MEDICA IN THE JEFFERSON MEDICAL COLLEGE, 
AND 
E. Q. THORNTON, M.D., 
DEMONSTRATOR OF THERAPEUTICS, JEFFERSON MEDICAL COLLEGE. 
DETROIT, MICH.: 
GEORGE S. DAVIS, PUBLISHER. 
1893. Reprinted from The Therapeutic Gazette, October 16, 1893. A STUDY 
OF THE 
Influence of Chloroform 
UPON THE 
RESPIRATION AND CIRCULATION. A STUDY OF THE INFLUENCE OF CHLOROFORM UPON 
THE RESPIRATION AND CIRCULATION. 
TO any one who endeavors to view the sub- 
ject of chloroform anaesthesia in an en- 
tirely impartial light two objects raise them- 
selves so high above all others that they form 
the peaks about which the smaller .questions 
must cluster. The first object on which the 
judicial eye rests is the firm belief of many 
clinicians that chloroform may cause sudden 
cardiac death; the second object to be seen is 
the statement of the Hyderabad Chloroform 
Commission that death from chloroform is 
never due to cardiac failure. In the support 
of the first belief we have not only wide clini- 
cal observation, but also the experimental evi- 
dences of a number of investigators. In sup- 
port of the second statement we have an array 
of experimental study not equalled by any 
other research extant, associated with an enor- 
mous number of negative observations on man. 
Negative observations because Lawrie alone in 
twenty-five thousand cases has never had a car- 
diac death. 
The controversy concerning the action of 
chloroform upon the animal organism has been 
waged so incessantly for many years, and has led 
to such extraordinary efforts for its elucidation 
and final decision, that any one who attempts 
to take part finds himself almost swamped by 
the number of statements and opinions which 
he is forced to regard. We have therefore 
approached this research feeling it was no or- 
dinary task, and that a path already so well 
travelled must be gone over with the utmost 
care if anything new or of value was to be 
discovered. 
In March, 1892, Surgeon Lieutenant-Colonel 
Lawrie, whose interest in this subject is recog- 
nized by the medical profession the world over, 
wrote to one of us (Hare), asking that another 
chloroform research be instituted, for which the 
government of His Highness the Nizam of Hy- 
derabad would pay. The express object of the 
research was the reconciliation of at least some 
of the contradictory conclusions reached by va- 
rious experimenters during the past few years. 
From the immense number of observations, 
in regard to the action of chloroform, in the 
laboratory and in the operating-room it is evi- 
dent that sufficient data are at hand to give us 
material to reach positive conclusions, and that 
the contradictory results hitherto obtained 
must have been reached by misinterpretation 
and error in experimental method, tinctured 
perhaps by opinions formed previous to the 
completion of a line of study. There are cer- 
tain facts in regard to chloroform which few 
will deny, the chief of which are that it has the 
advantage of rapid action without disagreeable 
preliminary or subsequent symptoms, its bulk 
is small, and its odor agreeable; but, more 
important than all, it is much more dangerous 
than ether. 
Though the Hyderabad Commission in their 
preliminary conclusions (page 30, paragraph 43) 
assert that ether is as dangerous as chloroform 
if given sufficiently to produce true anaesthesia, 
we believe that the safety of ether is so univer- 
sally recognized that this conclusion of the 
Commission can only be excused by the re- 
membrance that ether has probably been used 
as little by those who wrote this paragraph as 
chloroform is used in many parts of America. 
This possibility is made a probability when we 
read that "if surgeons choose to be content 
with a condition of semi-anaesthesia, it can no 
doubt be produced with perfect safety, though 
with discomfort to the patient, by ether held 
rather closely over the mouth. Such a condi- 
tion of imperfect anaesthesia would never be 
accepted by any surgeon accustomed to operate 
under chloroform. ' ' That this statement shows, 
to put it mildly, that the writer knows not 
whereof he speaks is proved by the universal 
employment of ether by hundreds of the best 
surgeons the world over in preference to chlo- 
roform. Further than this, medical literature 
contains so many statistical papers showing the 
small percentage of deaths from ether as com- 
pared with chloroform that this point need not 
be debated. 
There are certain other points in regard to 
the action of chloroform which may be put 
aside as settled, and therefore not needing fur- 
ther study, being generally received as beyond A Study of the Influence of Chloroform upon the Respiration and Circulation. 
3 
criticism, and we have made no experiments 
looking to their reproduction, but have devoted 
our efforts solely to the questions over which 
discussion still proceeds. Thus, all investiga- 
tors concur in the statement that chloroform, 
even in ordinary therapeutic quantity, acts as a 
powerful and constant depressant to arterial 
pressure. This conclusion has been reached 
by Bowditch and Minot and Coats, H. C. 
Wood and H. A. Hare, Gaskell and Shore, 
the Hyderabad Chloroform Commission Nos. 
1 and 2, and by every experiment in the re- 
search now carried out which forms this re- 
port. There is no evidence to the contrary, 
and practically it has never been denied. Gas- 
kell and Shore state, however, that chloroform 
may cause anaesthesia without lowering blood- 
pressure, and that chloroform causes primarily 
a rise of pressure. They also believe that the 
chief cause of the fall of arterial pressure is car- 
diac and not vaso-motor depression. The rise we 
have never seen except from struggles, and we 
have never been able to produce anaesthesia 
without lowering the blood-pressure, even when 
the drug was used in the smallest quantity capa- 
ble of causing anaesthesia and given as slowly 
as possible. We agree with the statement of 
the Hyderabad Commission that a fall of 
blood-pressure always occurs when chloroform 
anaesthesia is produced. 
We are also forced, as the result of our studies, 
to differ entirely with Gaskell and Shore in 
their statement that the fall of arterial pressure 
is due primarily to a weakening of the heart's 
action and not to paralysis (depression ?) of 
the vaso-motor centre. We believe that both 
factors cause the fall, but that the dominant 
factor is vaso-motor depression, because, as 
will be seen in several of bur tracings, the 
pulse-waves were quite strong, though the 
blood-pressure, through vaso-motor relaxation, 
was absolutely to the abscissa line, and we 
agree with Lawrie that no conclusions as to 
the action of chloroform when inhaled can be 
drawn from the injection experiments of Gas- 
kell and Shore into the arteries. One of our 
reasons for this belief is the entire difference in 
method necessary and the corresponding differ- 
ence in result. Another reason is that any pow- 
erful drug injected into the brain will cause a 
rise of blood-pressure. Even nitrite of amyl, 
the prince of vaso-motor paralyzants, will do 
this. (See Gaskell and Shore, page 17, para- 
graph 68.) 
We also believe that results obtained by such 
interesting methods of experimentation as em- 
ployed by Gaskell and Shore are not capable 
of giving us positively reliable information, as 
the conditions are so utterly at variance with 
those in which chloroform is given to man ; 
and, further, that their methods are such as to 
give room for fallacious results, which cannot 
be excluded by the greatest caution on the part 
of experimenters, experienced as they are. 
Secondly, it is not denied by any one, that 
we know of, that chloroform exerts a powerful 
depressant, paralyzant action on the respira- 
tory centre. This is agreed to by clinicians 
and by every one who has experimentally 
studied the action of the drug on the lower 
animals. (See results of collective investi- 
gation.) 
Thirdly, it is universally conceded that chlo- 
roform is_a lethal agent of great power when 
brought in direct contact with highly-vitalized 
tissues. 
Aside from these facts, there are a number of 
others in which we find ourselves strictly in ac- 
cord with the conclusions of the Hyderabad 
Commission. In order to make clear those 
points in which we agree and differ, we print 
the conclusions reached by the Commission, 
and to be found on page 17 of their official 
report.* 
" 1. Chloroform, when given continuously 
by any means which insures its free dilution 
with air, causes a gradual fall in the mean 
blood-pressure, provided the animal's respira- 
tion is not impeded in any way, and it con- 
tinues to breathe quietly, without struggling or 
involuntary holding of the breath, as almost 
always happens when the chloroform is suffi- 
ciently diluted. [See our Experiments 1, 4, 
13, 23, and 27 (Hare and Thornton).] f 
"As this fall continues the animal first be- 
comes insensible, then the respiration gradually 
ceases, and, lastly, the heart stops beating. [In 
every one of our experiments this course was 
followed as soon as struggles ceased (Hare 
and Thornton).] 
" If the chloroform is less diluted the fall is 
more rapid, but is always gradual, so long as 
other conditions are maintained ; and however 
concentrated the chloroform may be, it never 
causes sudden death from stoppage of the 
heart. The greater the degree of dilution the 
less rapid is the fall, until a degree of dilution 
is reached which rib longer appreciably lowers 
* These are not the final conclusions, published in the 
Lancet and elsewhere, which were drawn up for general 
readers, but from the more scientific and accurate deduc- 
tions of the research itself. 
j- It is unfortunate that space does not permit the re- 
production of every experiment made, or even every 
part of the ones given. As far as possible every valua- 
ble part has been included. A Study of the Influence of Chloroform upon the 
4 
again. The heart was in all these experiments 
very weak, but it recovered rapidly from its 
weakness, so we must conclude that the cardiac 
condition was one of weakness or depression 
and not paralysis or death. 
" 2. If the inhalation is interrupted at any 
stage, the fall of pressure still continues at a 
rate which depends altogether on the rapidity 
of the fall while the chloroform was being in- 
haled. This after-fall is probably due to ab- 
sorption of a portion of the residue of chloro- 
form in the air-passages after the stoppage of 
the inhalation. In this way it often happens, 
if chloroform is given rather freely, that though 
the respiration may be going on when the chlo- 
roform is discontinued, it afterwards stops. 
[Our results are identical with this conclu- 
sion.] 
"3. If the administration of the chloroform 
is stopped at an early stage the pressure very 
soon begins to rise again, and gradually be- 
comes normal. [See our Experiments 8, 13, 
17, 23, and 27 (Hare and Thornton).] But if 
the chloroform is pushed further, there comes a 
time, not easy to define, when the blood- 
pressure and respiration will no longer be re- 
stored spontaneously, although the heart con- 
tinues to beat after the inhalation is stopped. 
[See our Experiments 1, 5, 10, 13, 16, 17, 18, 
and 23, all of which confirm this conclusion 
(Hare and Thornton).] 
"4. If the fall has been very gradual, it may 
occasionally happen that the respiration stops 
completely, and still the blood-pressure rises 
again, the respiration recommencing sponta- 
neously in the course of the rise. [See our 
Experiments 12, 13, 17, and 26 (Hare and 
Thornton).] In the same way, when the in- 
halation has been discontinued, the respira- 
tion may stop during the after-fall of the blood- 
pressure and begin again spontaneously. As a 
rule, if the respiration has stopped, or even be- 
comes slow and feeble at the time when the in- 
halation is discontinued and artificial respira- 
tion is not resorted to, the fall in blood-pressure 
will continue until death ensues. [See end of 
our Experiments 1,5, 10, 13, 17, 18 (Hare and 
Thornton).] 
"5. There are two conditions which fre- 
quently disturb the gradual fall of the blood- 
pressure,-viz., struggling and holding the 
breath,-and it is only by great care that they 
can be avoided in animals. [Our results are 
entirely in accord with this.] 
" 6. Struggling, independently of any change 
in the respiratory rhythm, appears generally to 
raise the blood-pressure. [See our Experi- 
ments 13, 15, 16, 27 (Hare and Thornton).] 
the blood-pressure or produces anaesthesia." 
(See below.) 
With this entire statement our results are 
practically in accord, but we would like to 
qualify the words " however concentrated the 
chloroform may be, it never causes sudden death 
from stoppage of the heart" by saying it never 
has caused sudden stoppage of the heart in any 
of our experiments unless respiration ceased 
primarily. We make this modification because, 
as we will point out later in this report, we be- 
lieve circumstances may exist in which the dis- 
eased heart may stop suddenly under chloro- 
form. On the other hand, we do not believe 
that it is possible in a lower animal (the dog) to 
cause cardiac death by the freest possible use 
of chloroform by inhalation without causing 
primary respiratory arrest, and respiratory ar- 
rest having taken place, the death which fol- 
lows is partly due to asphyxia and partly to 
direct cardiac failure and vaso-motor paralysis. 
In reaching this conclusion one of us (Hare) 
is well aware that his position is directly op- 
posed to his conclusions published in a joint 
paper by H. C. Wood and himself in the 
Medical News of February 22,, 1890. The 
tracings shown in that paper, to prove that chlo- 
roform was capable of causing primary arrest of 
the heart, are all (except No. 5) tracings of 
experiments in which chloroform was injected 
directly into the jugular vein, which is an en- 
tirely different thing from its absorption from 
the lungs into the blood well mixed with air. 
Even quinine injected into the jugular vein 
will cause cardiac arrest. Further than this, 
this research has shown us that in only one of 
the three tracings presented by Wood and Hare 
did death certainly occur from cardiac failure, 
even when the drug was given intravenously,- 
namely, in their tracing No. 4. Perhaps if ar- 
tificial respiration had been resorted to recovery 
would have occurred, as our experiments have 
proved is possible even after both heart and 
respiration have apparently stopped. (See Nos. 
3, 13, 17, and 27, Hare and Thornton). The 
pulse-line in Tracing No. 3 (Wood and Hare) 
is more than reproduced by jugular injection in 
No. 14 in this research, and No. 5 (Wood and 
Hare) by inhalation in No. 23 (Part XV. and 
XVI.) of this research, and it will be noted that 
though the heart failed in these experiments to 
make a pulse-mark, for the time being, that it 
eventually recovered sufficiently to do so or was 
found beating when the chest-wall was opened 
or a needle was thrust into the heart. Again, 
in Experiment 13, in this research (Hare and 
Thornton), it will be seen that when the pen 
was practically at the abscissa it suddenly rose Respiration and Circulation. 
5 
In one case of a dog much weakened from 
phosphorus the pressure fell every time he 
struggled. [We agree with the first sentence, 
but believe that struggling and change in re- 
spiratory rhythm are inseparable. Of the facts 
in the second sentence we have no knowledge.] 
"7. When struggling is accompanied, as it 
often is, by acceleration of the respiration and 
pulse, especially if the respiration is deep and 
gasping, it leads to a more rapid inhalation of 
chloroform, and consequently to a more rapid 
fall of blood-pressure and a greater after-fall. 
[Compare our Experiments (Hare and Thorn- 
ton) 13, 16, and 27 with Experiment 23, in 
which there was no struggling and a gradual fall.] 
In order to keep the chloroform-cap or inhaler 
in its place during the animal's struggles, the 
administrator is obliged to hold it down more 
tightly over the nose and mouth, and this ma- 
terially assists in hastening the rapidity of the 
inhalation, and consequently of the fall in 
blood-pressure. [We agree with this state- 
ment.] 
" 8. The effect of involuntarily holding the 
breath, which, as anybody can prove by ex- 
perimenting upon himself, must happen when 
an inhaler saturated with chloroform is first 
applied to the face, is much more remarkable, 
the pressure often falling with great sudden- 
ness, while the heart's action is markedly 
slowed. [See Experiments 1 and 5 of Wood 
and Hare, No. 1 being reproduced in this 
paper.] As soon as the animal draws breath 
again the pressure rises as suddenly as it fell, 
but the gasping respiration which succeeds 
then causes very rapid inhalation of chloro- 
form with immediate insensibility and a rapid 
fall of blood-pressure which becomes danger- 
ous. [See our Experiment 13 (Parts IV., V., 
VI.), and Experiment 17. This fall is some- 
times dangerous and sometimes not. Cer- 
tainly not a dangerous fall in Tracing No. 
16 under atropine. Taking the paragraph as 
a whole, we agree with its statements en- 
tirely, and believe that the first action named 
is solely due to reflex inhibition through vagal 
and trigeminal irritation (Hare and Thornton).] 
"9. The combination of struggling with al- 
ternate holding the breath and gasping, which 
results if chloroform is applied closely to 
the face without sufficient dilution with air, 
causes violent fluctuations and then a speedy 
fall of the blood-pressure, which very soon 
leads to a dangerous depression with deep in- 
sensibility and early stoppage of the respira- 
tion. [See our Experiments 13 and 27 (Hare 
and Thornton).] The after-fall under these 
circumstances is rapid and prolonged (Vr). 
[We also find it rapid.] It is this combina- 
tion of events which causes struggling animals 
to go under chloroform so quickly. 
"io. The effect of holding the breath may 
occasionally cause a temporary fall of blood - 
pressure after the chloroform inhalation has 
been stopped, or even when the animal is quite 
out of chloroform. This fall is recovered from 
directly the animal breathes again. [We con- 
cur in this.] 
" n. Slight, continuous asphyxia, such as is 
produced by pressure on the neck by straps, a 
badly-fitting muzzle, or hinderance of the chest- 
movements by the legs being too tightly bound 
down, gives rise to exaggerated and irregular 
oscillations of the blood-pressure and slowing 
and irregularity of the heart's action. If it 
leads to, or is accompanied by, deep gasping 
inspiration, it is apt, like anything else which 
causes this, to increase the intake of chloroform 
and bring about a rapid decline of blood- 
pressure. [We concur in this conclusion.] 
" 12. Complete, or almost complete, as- 
phyxia, as by forcibly closing the nose and 
mouth, or closing the tracheal tube after 
tracheotomy, has an effect similar to, but more 
marked than, that produced by holding the 
breath, and the character of the trace corre- 
sponds precisely to that produced by irritation 
of the peripheral end of the cut vagus. The 
pressure falls extremely rapidly, sometimes al- 
most to zero, and the heart's action becomes 
excessively slow or even stops for a few 
seconds. 
"13. This effect of asphyxia is the result of 
stimulation of the vagi. The proof of this is 
(<z) that the trace corresponds exactly, as stated 
above, to that produced by direct irritation of 
the vagus; (A) division of both vagi entirely 
abolishes it; and (c) the administration of atro- 
pine, which paralyzes the vagus, also abolishes 
it. [Tracing No. 15 Part I. (Hare and Thorn- 
ton). That vagal irritation does account for 
some of the circulatory disturbance is no doubt 
true, but in reality the changes are chiefly vaso- 
motor in character. We have not found that 
either vagal section or vagal paralysis with atro- 
pine prevented these phenomena, although it 
may modify them. See Tracing Nos. 10 and 
17 (Hare and Thornton).] 
"14. In Trace 158 (Fick, No. 4), which was 
taken during asphyxia after a full dose of atro- 
pine, it will be seen that there is an alternately 
slow and rapid pulse, according to the phase of 
the respiratory movement, but no continued 
slowing of the heart, as in vagus irritation. 
But there was still a distinct fall of pressure 
after the atropine when the breath was held, 6 
A Study of the Influence of Chloroform upon the 
and it was thought that the slowing of the 
pulse above noted in this condition might be 
due to the disturbance of the heart from ten- 
sion in the pulmonary vessels in the absence of 
respiratory movement rather than to irritation 
of the vagi. To test this point Experiment 184 
was instituted. In this experiment the dog's 
chest was forcibly inflated with bellows con- 
nected by a tube with the trachea, and the 
effect of this proceeding was to cause a fall of 
pressure and slowing of the heart, exactly the 
same as in involuntary holding of the breath. 
The dog was then poisoned with atropine, after 
which inflation of the chest still caused a fall 
of but without slowing of the heart 
(vide Fick, Nos. 8 and 9). The fall of pressure 
must be in some degree independent of vagus 
irritation, which, however, usually accom- 
panies it. 
"15. It only remains to be considered 
whether the slow action or temporary stoppage 
of the heart, with great fall of pressure pro- 
duced by vagus irritation, is in itself an element 
of danger in chloroform administration, and if 
it is not, wherein the danger actually lies. [See 
note to paragraph 16 (Hare and Thornton).] 
" 16. The experiments in which deliberate 
irritation of the vagi was carried on during 
anaesthesia show unmistakably that irritation of 
these nerves diminishes rather than enhances 
the danger of anaesthetics. The effect upon 
the heart is never continuous, and as the vagus 
becomes exhausted, of when the irritation is 
taken off, the blood-pressure rises again, as it 
does when the same result is produced by 
asphyxia. The slowing of the heart and circu- 
lation which is produced by irritation of the 
vagus by any cause, such as holding the breath 
in chloroform administration, retards the ab- 
sorption and conveyance of chloroform to the 
nerve-centres, just as holding the breath, 
whether voluntary or involuntary, prevents 
chloroform from entering the lung; and of 
itself slowing or temporary stoppage of the 
heart in chloroform administration is not dan- 
gerous. [We shall point out later in this re- 
port how we differ from this conclusion, for we 
believe that true fatty heart, plus ventricular 
engorgement, plus vagal irritation, plus possible 
valvular disease, and, finally, plus extreme 
vaso-motor relaxation, may result in death in 
frightened persons. While this is not, scien- 
tifically speaking, a cardiac death from chloro- 
form, practically the chloroform is the last 
straw which upsets the cardiac balance. How- 
ever, Lawrie and his colleagues recognize this as 
well as ourselves (see paragraph 38, Hare and 
Thornton).] 
" i"j. To answer the second part of the last 
question in paragraph 15 is easy enough, if it is 
kept in mind that the effect of vagus irritation 
upon the heart is never continuous; and in 
chloroform administration, as the pressure rises 
again after the slowing of the heart and tempo- 
rary fall of pressure produced by any form of 
asphyxia, violent respiratory efforts with bound- 
ing heart's action lead, as in the case of strug- 
gling, to a rapid and dangerous inhalation of 
chloroform, and consequent rapid and danger- 
ous decline in blood-pressure. [We believe in 
the healthy animal or man that this is true.] 
It is, in fact, the temporary exhaustion of the 
vagi after stimulation that is to be feared, and 
not the actual stimulation as long as it is 
continued. 
"18. In accordance with this fact it will be 
found that in chloroform administration neither 
holding the breath, even if involuntary, or 
vagus inhibition can be kept up beyond a cer- 
tain time; and if the chloroform is not re- 
moved from the face, one or both of two 
things happen : (1) when the animal breathes 
again it takes deep and gasping inspirations, 
the lungs become filled with chloroform, and 
an overdose is taken in with extreme rapidity; 
or (2) when the restraining influence of the 
vagus is taken off the heart, through the irrita- 
tion ceasing or the nerve becoming exhausted, 
the heart bounds on again, and the circulation 
is accelerated in proportion. The blood then 
becomes quickly saturated with chloroform, and 
an overdose is at once conveyed to the nerve- 
centres. [We believe this is true of the healthy 
heart, but not of one engorged with blood 
which has undergone fatty degeneration. This 
is only an hypothesis, however, as we have no 
experimental basis for this belief (Hare and 
Thornton).] The theory which has hitherto 
been accepted is that the-danger in chloroform 
administration consists in the slowing or stop- 
page of the heart by vagus inhibition. This is 
now shown to be absolutely incorrect. There 
is no doubt whatever that the controlling in- 
fluence of the vagus on the heart is a safe- 
guard, and that it is the exhaustion of the 
nerve which is dangerous. [We believe that 
this conclusion is more theoretical than practi- 
cal (Hare and Thornton).] 
"19. It can be readily understood how a 
condition in which the pulse is rapid and 
bounding, with high blood-pressure, leads to 
more rapid absorption of chloroform from the 
lungs and a more rapid propulsion of the chlo- 
roformed blood to the medulla oblongata, and 
consequently to a more rapid paralysis of the 
respiratory and vaso-motor centres and pre- Respiration and Circulation. 
7 
cipitous fall in the blood-pressure. Such a 
condition is produced in some cases by ether 
or by division of both vagi, or by a full dose 
of atropine. Not only is the poisoned blood 
carried more swiftly to the vital centres in 
these cases, but added to this there is the fact 
that as*the heart is already doing its 
before the chloroform is given, it is unable to 
stave off by increased work the fall in pressure 
that occurs when, the vaso-motor centre is 
paralyzed. On the other hand, it seems clear 
from Experiment 92 that the direct action of 
chloroform upon the heart's substance is not 
the cause of the fall of pressure that occurs 
when it is inhaled. 
[That we (Hare and Thornton) agree in 
general with these conclusions (paragraphs 15, 
16, 17, 18, and 19) is shown by the following 
extract from the research of Wood and Hare 
in the Medical News, February 22, 1889 : 
"The theory has from time to time found 
advocates that the vapors of chloroform may, 
by irritating the larynx and adjacent parts, 
cause arrest of the heart through a reflex in- 
hibition. To test the possibility of this, we 
have made a number of experiments. When 
the tracheal canula is tied tightly into the 
trachea some distance below the larynx, it is 
evident that the latter organ is isolated from 
the general respiratory tract, and that chloro- 
form injected into it will exert only a local in- 
fluence. In all the experiments which we 
have made in the way just indicated, the in- 
jection has been followed by an immediate and 
very pronounced primary fall of the pressure, 
followed, after a very brief interval, by a rise, 
which usually reaches decidedly above the 
norm. As an example of one of these experi- 
ments, we give the preceding tracing. [See 
Tracing 1, Wood and Hare, here appended.] 
"The primary fall of arterial pressure, which 
has just been spoken of, can scarcely be pro- 
duced except by reflex inhibition of the heart 
or of the vaso-motor centres, while the second- 
ary rise is probably the result of a reflex vaso- 
motor spasm. In order to throw light upon 
this question, we have made experiments by in- 
jecting chloroform into the Larynx after division 
of the pneumogastric nerves, the trachea being 
ligated so as to prevent the entrance of the 
anaesthetic into the lungs. [See Tracing 2, 
Wood and Hare, here appended.] 
" In making practical application of the ex- 
periments thus discussed, it must be noted that 
in no case have we succeeded in completely ar- 
resting the heart's action by injecting chloro- 
form into the larynx, and as the chloroform 
was injected in liquid form, it is plain that the 
irritation was more intense than could be pro- 
duced by the mere vapors of the anaesthetic, 
however concentrated; therefore, while it 
must be considered that it is possible for a re- 
flex inhibitory arrest of the heart to occur 
during the inhalation, such an accident is ex- 
tremely improbable, and we consider it prac- 
tically certain that a heart so arrested could, a 
few seconds later escaping from the inhibitory 
control, recommence its beat. [See our Ex- 
periment 15 (Hare and Thornton).] It cer- 
tainly has never been proved that chloroform 
can cause in the human subject permanent re- 
flex inhibitory cardiac arrest, and as our experi- 
ments upon the dog have failed to cause arrest, 
we consider it very improbable that reflex car- 
diac arrest is ever produced in man by chloro- 
form." To this we wish to add, unless the 
cardiac disease or condition is such as to be un- 
able to withstand any shock whatever (Hare 
and Thornton).] 
" 20. In Experiment 92 repeated injections 
of 20 minims of chloroform were made into the 
jugular vein, and its effect was not to paralyze- 
the heart, but to produce anaesthesia and a 
gradual fall of blood-pressure, exactly as if the 
chloroform had been inhaled. In Experi- 
ment 72, after a considerable amount of ether 
had been injected into the jugular vein and a 
bounding condition of pulse had been pro- 
duced, the effect of injecting chloroform into 
the jugulars was much greater and the fall of 
blood-pressure much more rapid and dangerous 
than is the case when chloroform alone was in- 
jected. Granting; then, the truth of Ringer's 
conclusions from experiments on the frog's 
heart (which have not been repeated and con- 
firmed by the Commission), that chloroform has 
a gradual paralyzing effect upon the heart's tis- 
sue, we must conclude that such an effect, in 
the degree in which alone it could occur in the 
practical inhalation of chloroform, would rather 
be a source of safety than of danger. [With 
these conclusions we have to entirely disagree, 
and we cannot understand how results so com- 
pletely at variance with our own and with those 
of Wood and Hare could have been arrived at. 
(See Tracings Nos. 19 and 20.) The tracings 
we present do not admit of wrong interpreta- 
tion. Perhaps the difference lies in the fact 
that in our studies enough water was added to 
the chloroform to carry it en masse to the heart, 
whereas in the East Indian studies the pure un- 
diluted drug was injected, and had not suffi- 
cient volume to reach the heart, and was grad- 
ually volatilized in the vein, and so produced 
•a gradual effect. (This is shown in Tracing 
No. 8, Hare and Thornton.) We find the in- 8 
A Study of die Influence of Chloroform upon the 
jection of from 2 to 4 cubic centimetres of chlo- 
roform into the jugular vein causes arrest of 
respiration, rapidly followed by cardiac arrest, 
which is not secondary to the respiratory fail- 
ure, but to a primary action of the chloroform 
on the heart-muscle, which is found more re- 
sponsive to stimulation. We have made this 
experiment over one hundred times. 
It having been denied that chloroform, when 
injected into the jugular vein, causes cardiac 
depression, and the recent experiments of Leaf 
and his colleagues in Hyderabad having been 
cited to support this view, let us discuss the 
facts before us. In these researches they found 
when chloroform was given in excessive amount, 
that the pen fell to the abscissa line and failed 
to record a pulse-wave, but that a needle in 
the heart-muscle continued to beat for many 
seconds. While at first glance these results, 
which we have also obtained (see our Experi- 
ments 19 and 20), seem to prove that the 
cardiac arrest is only apparent and not real, 
in reality they have been given an importance 
far in excess of their value. We have proved 
again and again that the movement of the 
needle may be due, not to a true cardiac con- 
traction, but to inco-ordinated contraction of 
one of the ventricles, and to contractile move- 
ments of bands of the cardiac muscle, which 
movements are very often rhythmical enough 
to make the needle beat regularly. We have 
found this needle movement taking place even 
after an injection of chloroform had been sent 
directly into the heart through the chest-wall, 
and in a heart the muscle of which failed to 
respond to any strength of faradic irritation, 
except in those parts which had not come in 
contact with the poison. 
Further than this, if an animal be given 
very large doses of chloroform intravenously 
or by direct intracardiac injection, respira- 
tion invariably ceases if the amount be large 
enough, and if the chest be opened one con- 
dition will be constantly found-,-viz., the heart 
so widely dilated as to fill the pericardium al- 
most to bursting, and the cavities, particularly 
the ventricles, engorged with blood. Although 
they may still be feehjy contracting, the con- 
traction is abortive and fails to cause arterial 
flow. If the drug has been used intravenously, 
by the jugular, the blood in the right and left 
heart will be found red, provided death has come 
on rapidly. If not, it will be dark and venous. 
The lungs will be found of that peculiar pink 
hue due to altered blood. If the injection has 
been cardiac, it will be found that the ventricle 
with which the poison has come in direct con- 
tact has become paralyzed, while the other is 
making fairly good efforts to work. (See our 
Experiment 21, Hare and Thornton.) When 
the injection takes place into the right ventri- 
cle, so that the poison passes to the left cavity, 
both ventricles fail to act voluntarily or to 
faradism. (See our Experiment 25, Hare and 
Thornton.) Chloroform is capable, therefore, 
of causing death of the cardiac muscle when- 
ever it comes in contact with it, and that there 
is no possibility of this arrest being due to vagal 
irritation is proved by experiments in which 
vagal section preceded the use of the chloro- 
form. (See our Experiments 22, 24, and 25.) 
We doubt whether the last sentence of para- 
graph 20 is justified by our present knowledge.] 
"21. The committee discussed the advisa- 
bility of cutting the vagi some time previous to 
experimenting on the blood-pressure with chlo- 
roform. The effect of this procedure is to 
cause continuous rapid action and tendency to 
exhaustion of the heart, as well as to degenera- 
tion of the terminal branches of the nerves in 
the heart if the animal lives sufficiently long. 
Such experiments might be of some interest 
theoretically, and also have had a practical 
bearing upon the condition of the heart in cer- 
tain cases of chronic alcoholism ; but the com- 
mittee decided not to perform them, as they con- 
sidered the end to be gained did not justify the 
pain they would have inflicted. [We have not 
made this particular experiment, but we found 
that vagal section immediately before the drug 
was used did not materially alter the result.] 
"22. In Experiment 178, the case of a dog 
that had had morphine, remarkable slowing 
and even temporary cessation of the heart's 
action occurred again and again at the same 
moment as the respiration stopped, but the 
heart invariably recovered itself and began 
again to beat regularly before any steps were 
taken to restore the animal, and without any 
respiration occurring. We found in this case 
that it was possible to restore the animal even 
after unusually long intervals had been allowed 
to elapse between the cessation of natural and 
the commencement of artificial respiration. 
The failure of the heart, if such it can be called, 
instead of being a danger to the animal, proved 
to be a positive safeguard by preventing the 
absorption of the residual chloroform and its 
distribution through the system. [We have 
not made any experiments on this point.] 
" 23. The effect of artificial respiration after 
the natural respiration has ceased is to cause an 
alternate rise and fall of small amount in the 
blood-pressure, the trace thus formed upon the 
drum being a coarse imitation-altered some- 
what by the shaking of the table-of the nat- Respiration and Circulation. 
9 
ural respiratory curve. [We concur. (See our 
Experiments 3 and 27, Hare and Thornton.)] 
The difference consists chiefly in the fact that 
the artificial rise and fall is more abrupt than 
in normal breathing, and that the rise always 
coincides with expiration or compression of the 
chest. After artificial respiration has been con- 
tinued for a certain time the blood-pressure 
begins to rise again, and a little later natural 
respiration returns. [We concur in this re- 
sult.] 
"24. The effect of artificial respiration in 
restoring an animal after the respiration had 
stopped was always marked. [See our Ex- 
periments 3 and 27 (Hare and Thornton). 
We therefore concur, as qualified by the next 
paragraph.] In a few exceptional cases, such 
as No. 159, a phosphorus dog, and No. 142, a 
horse which had an enormous overdose, al- 
though the artificial respiration was commenced 
as soon as possible after the breathing was no- 
ticed to have stopped, it was not successful. 
"25. Complete stoppage of the respiration 
always means that an overdose has been ad- 
ministered, and the overdose may have been so 
great as to render restoration impossible. It is 
impossible to say whether, after chloroform 
has been pushed and then discontinued, the 
respiration will be restored spontaneously or 
not, and it is never in any case certain that arti- 
ficial respiration will restore the natural respira- 
tion and blood-pressure, no matter how soon it 
is commenced after the respiration stops. [See 
our Experiments 1 and 5 (Hare and Thorn- 
ton).] A great deal depends upon the amount 
of the after-fall: in some cases, even after the 
respiration has been restored, the pressure con- 
tinues to fall and respiration again ceases, and 
artificial respiration then fails. We thus find 
z respiration restored by artificial respiration 
while chloroform is still being absorbed, and 
this tends to show that artificial respiration 
does not merely pump the chloroform out of 
the blood, but exerts considerable influence in 
exerting the natural respiration. 
" 26. The time which elapses before artifi- 
cial respiration succeeds in restoring natural 
respiration varies very greatly. In one case 
(No. 116) it was continued for eleven minutes 
before the first natural gasps commenced. 
This period is undoubtedly prolonged in some 
cases by a condition of physiological apnoea 
which renders it unnecessary for the animal to 
breathe. Consequently, whenever the pressure 
rose considerably during artificial respiration, 
it was stopped, and the animal then generally 
breathed after a few seconds. [Whenever 
apnoea developed, the fall of pressure would 
persist and a rise not take place (Hare and 
Thornton).] 
"27. The time which may be allowed to 
pass with impunity before commencing artifi- 
cial respiration also seems to vary consider- 
ably. This point was not particularly attended 
to in the manometer experiments 162 and 178, 
which were instituted to test the truth of the 
opinion formed by the sub-committee, that 
morphine had some slight action in impairing 
the efficiency of artificial respiration. In these 
cases the commencement of artificial respira- 
tion was postponed for more than two minutes 
after respiration ceased, and was successful; 
but this is certainly far above the average in- 
terval that can be allowed with safety. The 
success of artificial respiration in restoring the 
blood-pressure is, in some cases, very remark- 
able. In Experiment 40 the heart had appar- 
ently ceased beating, and the dog was believed 
by every one present to be dead, and yet re- 
covered with artificial respiration. The success 
in this instance is due to the fact that concen- 
trated chloroform had been pushed for two 
minutes, regardless of the breathing, and the 
stoppage of the heart was due to stimulation of 
the vagus through asphyxia. The animal was 
therefore easily restored, as he was suffering 
more from asphyxia than from chloroform- 
poisoning. 
" 28. It corresponds to those cases, which 
are so often reported, in which dangerous fail- 
ure of the heart is said to have occurred some 
minutes after the administration of chloroform 
had been discontinued, and which are some- 
times restored, and sometimes not, by artificial 
respiration. There is nothing at all sudden 
about the failure of the heart in these cases, 
but the attention of the chloroformist, which 
has been wandering, is suddenly called to the 
fact that the patient is apparently dead. When 
the animal was really dead, it was found in 
some cases that artificial respiration still main- 
tained a small amount of mean pressure in the 
manometer. In others the pressure seemed to 
fall to the zero line between each compression 
of the chest. [We reach a similar conclu- 
sion.] 
"29. The dangers of too vigorous artificial 
respiration were illustrated in some of the acci- 
dental deaths. In one case the liver was badly 
ruptured, and in another the pleural cavity was 
full of blood. In three cases (Nos. 80, 92, and 
103) rhythmical movements of the diaphragm 
were noticed after the heart had ceased beat- 
ing and after the chest had been opened. It 
is remarkable that in two of these cases the 
splanchnic nerve had been divided. The third 10 
A Study of the Influence of Chloroform upon the 
was a case in which chloroform had been in- 
jected into the jugular, and in this case there 
was a synchronous movement of the jaw as 
well. In all, death and stoppage of the heart 
had occurred gradually, and in No. 103 the 
heart was still irritable. These movements 
cannot be called respiration, though the last 
gasp of a dying animal-that ineffective jerk 
of the diaphragm which is such a fatal symp- 
tom-is very likely in many cases a movement 
of the same character. Similar movements, 
which were continued much longer, occurred 
in Experiment 104, after the thorax was 
opened, while the heart was still beating. 
Still more remarkable convulsions of the mus- 
cles of the jaws, ears, and forefeet occurred in 
Experiment 167, in the case of a dog that had 
been poisoned with nicotine. These move- 
ments continued at regular intervals for more 
than ten minutes after death, and were suffi- 
ciently forcible to jerk the handles of a pressure 
forceps fixed on the end of the tongue off the 
table at each spasm. In a rabbit in Experi- 
ment 153 the auricles of the heart continued to 
beat rhythmically for three hours after it was 
supposed to be dead from chloroform and its 
thorax had been laid open. Irritability of the 
heart after death was noticed in many cases, 
but seemed to be most marked in cases where 
ether had been used. [We have made no 
studies in regard to this point.] 
" 30. Chloroform injected into the heart 
through the jugular vein did not cause clotting 
of the blood, as was the case when ether was 
injected. [Chloroform did cause clotting in 
our experiments (Hare and Thornton).] 
"31. In the course of the experiments of the 
committee various drugs were administered, in 
order to ascertain if they had any effect in 
modifying the action of chloroform. The re- 
sult showed that none of them had any effect 
in preventing the typical descent of the blood- 
pressure that occurs when chloroform is in- 
haled. Atropine, when given in a dose suffi- 
cient to paralyze the vagi, of course prevents 
the action of those nerves in asphyxia, and, by 
increasing the action of the heart, it appears to 
cause a more rapid descent in the blood- 
pressure when chloroform is inhaled, as has 
been already explained. [We cannot agree to 
this. (See our Experiments 10, 16, 17, and 
18, Hare and Thornton.)] Morphine appeared 
in Experiment 162 to render the rise in blood- 
pressure that occurred when the chloroform 
was discontinued slower and less complete and 
to bring about a more or less permanent condi- 
tion of anaesthesia. It may be noted that the 
animal used in this experiment was a monkey, 
and in other experiments with monkeys, when 
no morphine had been given, it was remarked 
that the animal, after a few inhalations of chlo- 
roform, would often lie quite quiet, in a state of 
semi-sensibility, for a long time without further 
inhalations ; still, this condition was much more 
marked in Experiment 162 than in any of the 
others. No action of this kind was noticed in 
the dog (Experiment 178); but other experi- 
ments (Nos. 90 and 94) showed that pariah 
dogs are very indifferent to the action of mor- 
phine, and it is probable that the dose of mor- 
phine in this case was insufficient to bring 
about the condition noted in the monkey. 
The peculiar behavior of the heart in Experi- 
ment 178 was not the result of the previous ad- 
ministration of morphine, for a similar phenom- 
enon had occurred in other cases (49 and 60) 
in which no morphine had been given. Ex- 
periments 162 and 178 prove conclusively that 
morphine has no effect in shortening the period 
that may be allowed to elapse between the ces- 
sation of natural respiration and the commence- 
ment of artificial respiration. [We have al- 
ready shown in Nos. 10, 16, 17, and 18 of our 
experiments that atropine seems to produce a 
very gradual fall of pressure and to preserve the 
circulation. With the other drugs we have not 
experimented (Hare and Thornton).] 
"32. The other drugs used had no effect 
upon the action of chloroform, except when 
their own special action became the leading 
feature in the case, as, for instance, during the 
vomiting from apomorphine (Experiment 104, 
Fick, No. 9) or the convulsions produced by 
nicotine (Experiment 167). 
"33. In order to test the alleged danger 
from shock during chloroform administration, 
the committee performed a very large number 
of those operations which are reputed to be 
particularly dangerous in this connection,■'such 
as extractions of teeth, evulsion of nails, sec- 
tion of the muscles of the eye, snipping of the 
skin of the anus, etc. In many cases the opera- 
tion was performed when the animal was merely 
stupefied by the chloroform and not fully in- 
sensible. In such cases a slight variation in 
the blood-pressure would sometimes occur, such 
as one would expect from the irritation of a 
sensory nerve or from the struggling that en- 
sued, but in no case in any stage of anaesthesia 
was there anything even suggestive of syncope 
or failure of the heart's action. In thrusting a 
needle into the heart there was often a momen- 
tary but well-marked fall of blood-pressure, but 
even this was absent in all other injuries. If 
chloroform really has any power to increase 
the tendency to shock in operation, it is im- Respiration and Circulation. 
11 
possible to believe that it would not have been 
manifested to some degree at least in one or 
other of these numerous experiments. The 
Commission was, however, not content with 
this negative result, and determined to ascer- 
tain the effect of direct irritation of the vagi 
during continued chloroform administration. 
The result of such experiments (Nos. 65, 117, 
and others) proved that inhibition of the 
heart's action prevented rather than assisted 
the fatal effects of prolonged chloroform in- 
halation. An animal that was put into a con- 
dition of extreme danger (from which it could 
only be restored by means of artificial respira- 
tion) by inhalation of chloroform for one 
minute, recovered spontaneously and readily 
after five minutes of chloroform, together with 
inhibition of the heart, by electrical irritation 
of the vagus carried on simultaneously. In one 
of these experiments (No. 117) chloroform was 
pushed for seven minutes; and during con- 
tinued irritation of the vagus the animals re- 
peatedly came round without artificial respira- 
tion. The danger really begins when the irri- 
tation is discontinued or fails to inhibit the 
heart, and thus enables the chloroform in the 
lungs to be rapidly absorbed and thrown into 
the blood by means of artificial respiration ; for 
animals in which this was done, although they 
showed a tendency to recover when the chloro- 
form and irritation of the vagus were discon- 
tinued, afterwards died rapidly. 
" 34. On another occasion, during Experi- 
ment 117, the animal was very nearly killed by 
a comparatively short inhalation of chloroform, 
owing to the electrodes becoming accidentally 
short-circuited and failing to keep up the irri- 
tation of the vagus. Something similar oc- 
curred in Experiment 177, the effect of the 
irritation of the vagus passing off while the 
chloroform was still being pushed, and thus 
putting the animal into a condition of extreme 
and unexpected jeopardy. Nothing could be 
more striking than these near approaches to 
accidental death from failure to irritate the 
vagus efficiently. 
"35. Other experiments were made to test 
the truth of the statement that chloroform in- 
creases the action of electrical stimuli applied 
to the vagus, and showed conclusively that it 
has no such effect. In one instance only the 
inhibition seemed to be intensified as the chlo- 
roform was commenced and diminished when it 
was discontinued; but apart from the fact that 
the supposed effect ceased much too suddenly, 
a repetition of the experiment on the same and 
other animals showed that there was in reality 
no such effect. The increased inhibition in 
this instance was due to the chloroformist com- 
pelling the attendant who was holding the 
electrodes to change his position, and thus 
making him unconsciously apply them more 
efficiently. When the chloroformist withdrew 
thqy were restored to their former position. 
This affords an instance of the care that has to 
be taken in making experiments if one is not to 
be deceived. 
" 36. To test the effect of shock due to vaso- 
motor change rather than affection of the heart, 
Goltz's experiment on the frog was repeated on 
three dogs. In one there was slight lowering 
of pressure, which was not extensive, but in 
the others no effect was produced at all. Other 
operations which seemed likely to produce 
shock, such as violent blows upon the testicle, 
were singularly devoid of effect. Failing to 
lower the blood-pressure by any of these 
methods, recourse was had to section of the 
splanchnics, but the low condition of blood- 
pressure this produced appeared, like stoppage 
of the heart from vagus irritation, to be a 
source of safety rather than of danger during 
chloroform administration. In this connection 
Experiment in may be studied. There was 
not much external hemorrhage, but the splanch- 
nics were divided,-a proceeding which, as is 
often said, bleeds the animal into his own ves- 
sels. The pressure was after this extremely 
low, but chloroform was repeatedly given and 
various other actions taken, and then chloro- 
form had to be pushed on a saturated sponge 
inclosed in a cap for eleven minutes before 
respiration ceased. 
"37. The experiments on dogs that had 
been dosed with phosphorus for a few days pre- 
viously show that the fatty, and consequently 
feeble, condition of the heart and other organs 
so produced has no effect in modifying the ac- 
tion of chloroform. The ease with which 
vagus irritation and the Glasgow trace could 
be produced in these animals, by even slight 
degrees of asphyxia (vide Experiment 148), was 
very remarkable; but this was equally the case 
in dogs that had been given phosphorus only a 
few hours before the experiment, and whose 
organs were not yet fatty (vide. Experiment 
156). Many of these cases were in the last 
stage of phosphorus-poisoning, and several of 
their companions died without any experiment 
having been performed on them, before or on 
the same day as they did (yide the low state of 
blood-pressure in Experiment 163). [We have 
no experience to offer (Hare and Thornton).] 
Numerous attempts were made in these animals 
to produce shock by operations in the re- 
cumbent and vertical positions, but with- 12 
A Study of the Influence of Chloroform upon the 
out any result more than in those that were 
healthy. 
"38. The truth about the fatty heart appears 
to be that chloroform per se in no way endan- 
gers such a heart; but, on the contrary, by 
lowering the blood-pressure, lessens the work 
that the heart has to perform, which is a posi- 
tive advantage. But the mere inhalation of 
chloroform is only a part of the process of 
the administration in practice. A patient 
with an extremely fatty heart may die from 
the mere exertion of getting upon the oper- 
ating-table, just as he may die in mounting 
the steps in front of his own hall-door, or from 
fright at the mere idea of having chloroform or 
of undergoing an operation, orf during his in- 
voluntary struggles. Such patients must in- 
evitably die occasionally during chloroform 
administration, and would do so even were 
attar of roses or any other harmless vapor sub- 
stituted for chloroform." z 
[We agree entirely with this statement; but 
as chloroform has confessedly some cardiac 
action and a very positive vaso-motor and 
respiratory effect, the fatal result might be 
more direct.] 
SUMMARY. 
Having given the evidence we have accumu- 
lated, let us see what practical deductions may 
be drawn. 
From a careful study of the experiments so 
far reported, from studies made by one of us 
some two years ago with H. C. Wood, and, 
finally, from the careful series of experiments 
(the tracings of which we herewith append), 
we believe that the question can be settled by 
the acceptance of both views in a modified 
form, or, in other words, that there is no real 
antagonism in the beliefs that chloroform kills 
by depression of the heart or depression of the 
respiration. 
We very positively assert that chloroform 
practically always kills by failure of respiration 
when administered by inhalation, provided- 
and this provision is most important-that the 
heart of the anaesthetized is healthy and has 
not been rendered functionally incompetent 
by fright or violent struggles, or, again, by 
marked asphyxia. By a healthy heart we 
mean one which has not undergone true fatty 
degeneration, or has not so severe a valvular 
lesion as to make the slightest variation in the 
even tenor of the circulation fatal. 
As positively as we assert that chloroform 
kills primarily by respiratory failure, so do we 
also assert that in excessive dose by inhalation 
it has a depressant effect on the circulation, 
which is chiefly due to centric vaso-motor de- 
pression, with final depression of the cardiac 
muscle itself. Depression of the cardiac mus- 
cle alone is never great enough to cause death 
when the chloroform is given by inhalation, 
but we believe that gradual asphyxia, with the 
direct depression of the circulation, may do 
much towards producing a fatal result, for 
vaso-motor integrity is almost as necessary to 
life as an intact cardiac mechanism. This cir- 
culatory depression has been considered a safe- 
guard because it was supposed to prevent chlo- 
roform going to the vital centres ; but in reality 
it is no safeguard, because profound circulatory 
depression is as great an evil as respiratory nar- 
cosis. That the circulatory depression may be 
dangerous is not only evident, but it is stated to 
be so by the second Hyderabad Commission 
itself at the end of paragraph 8. This circulatory 
depression may be so profound that recovery is 
impossible even with the most thorough artifi- 
cial respiration, a fact stated by the second 
Hyderabad Commission in paragraph 25, 
which we quote in this paper. This empha- 
sizes the fact that we cannot afford to totally 
ignore the effect of chloroform on the circula- 
tion, and we cannot consider the patient in 
danger of circulatory failure only when the 
respiration ceases, but as soon as it becomes 
abnormal. On the other hand, we should re- 
member that, even if chloroform has been 
given properly, the arterial pressure may be so 
low as to give no pulse in the radial artery, and 
yet the circulatory system be ready to respond 
at once when the drug is removed. If, there- 
fore, the chloroform is properly administered, 
is there danger of its circulatory effect in man ? 
We think that it is just at this point that our 
research, and every other research on animals, 
fails, and necessarily fails, to produce a positive 
reply. The variation in the action of a drug 
on a diseased individual from its effect on the 
normal one is notorious, and we have no right 
to dogmatically assert that there is absolutely 
no danger of circulatory depression in man, 
even if we found no evidence of failure in dogs, 
because there may be many idiosyncrasies or 
variations, through disease in the human being, 
which may completely reverse the results of 
experiments on healthy animals. 
In other words, supposing that the amount 
of depression from very full doses of chloroform 
equals 25 units, this amounts to little in the 
normal heart; but if the heart be depressed 25 
additional units by disease, the depression of 
50 units may be fatal, particularly if to this 50 
is added 25 units more of depression through 
fright and cardiac engorgement, through dis- 
ordered respiration or struggling. That true Respiration and Circulation. 
13 
depression of the heart-muscle may take place 
under chloroform seems to us most undoubted, 
and we think that the tracings in every research 
that we have seen support this view. There is 
always a decrease in cardiac power manifested 
by the decrease in the force of the individual 
pulse-beat, and this passes away only if chloro- 
form is removed early enough. We also agree 
with McWilliams that from the very first in- 
halation of chloroform there is a constant ten- 
dency to cardiac dilatation. 
We come, finally, to the all-important ques- 
tions : 
1. Is chloroform a safe anaesthetic ? 
2. Are we to watch the pulse or respiration 
during the use of the drug, and what are the 
signs in the respiratory function indicative of 
danger to the patient ? 
3. What is the true cause of death from 
chloroform ? 
4. Is death from chloroform possible when 
it is properly administered ? 
5. Under what circumstances is the surgeon 
to use chloroform in preference to the less dan- 
gerous anaesthetic ether ? 
6. What is the best way of administering 
chloroform ? 
To the first question the answer is, Yes, for 
the majority of cases, provided it is given by 
one who is skilled in its use, and not only knows 
how to give it, but to detect signs of danger. 
It is not so safe as ether at any time, other 
things being equal, and never so safe in the 
hands of a tyro. 
To the second question the answer is, Watch 
the respiration, because as soon as enough chlo- 
roform is used to endanger the circulation, the 
respiration will show some signs of abnormality, 
either in depth, shallowness, or irregularity. 
In other words, the very effect of the drug may 
be to cause such deep and rapid respirations 
that an excessive quantity of the drug is taken 
into the lungs and continues to be absorbed 
even after the inhaler is withdrawn. 
As there is always a fall in pressure under 
chloroform, it is difficult to feel the radial or 
temporal pulse, and the respiratory centre rec- 
ognizes the degree of arterial depression which 
its sister vaso-motor centre has permitted by 
finding that its blood-supply is insufficient. 
As respiration fails first, it should be watched 
first. Finally, it is only by watching the res- 
piration that we can tell how much chloroform 
the patient is getting. We do not watch this 
function for danger alone, but to tell us of fhe 
dose. 
The answer to Question 3 is that death is 
always due in the healthy animal to respiratory 
failure accompanied by circulatory depression, 
which latter may be severe enough to cause 
death, even if artificial respiration is used skil- 
fully. Death only occurs in the healthy ani- 
mal when chloroform is given in excessive 
quantities. 
Question 4 is impossible to answer for man 
from the basis of experimentation, as we can- 
not produce identical diseased states in animals 
with those developed under various conditions 
in man. The physician having a case of heart- 
disease should always advise the patient of the 
danger of any ansesthetic, and he should re- 
member, whether it is wise to tell the patient 
or not, that anaesthesia always means a step 
towards death, even in the healthiest of men. 
In the event of a death under chloroform, the 
physician is not to blame if he has taken proper 
preliminary precautions and given the chloro- 
form properly. 
Every one is agreed that the patient taking 
chloroform should have plenty of fresh air, and 
in India we understand that, to all intents and 
purposes, patients are operated on in the open 
air, at least as compared to the closed rooms 
necessary in America and Europe. This free 
supply of air is important, whether we believe 
death to be imminent from cardiac or respira- 
tory failure; but this supply of air matters little 
to the patient if he does not breathe freely, nor 
does the dose of chloroform amount to aught 
if it is not drawn into the chest. The dose of 
chloroform is not the amount on the inhaler, 
but the amount taken into the chest, and, 
finally, the amount absorbed by the blood- 
vessels. The rapidity and depth of respiratory 
movements is, therefore, as Lawrie asserts, the 
entire key to the situation. We watch a wind- 
mill over a well to see if it is pumping into a 
reservoir a given quantity of water. If the 
windmill works irregularly, so that we know 
its pumping action is deranged, we separate it 
from the pump until it works steadily. Simi- 
larly we withdraw chloroform, as Lawrie says, 
whenever respiration becomes disturbed in 
rhythm or when struggling disturbs it, because 
it is the first indication that the drug's action 
is uncertain, and because there is no telling the 
dose which is absorbed. While watching the 
respiration will not warn us of a sudden car- 
diac arrest in fatty heart plus chloroform de- 
pression, neither will the pulse give us such 
warning, and we are confident that the state- 
ment of the Hyderabad Commission, that the 
respiration should be watched, is correct, for we 
believe, from a long series of observations, 
that gradual cardiac failure never occurs with- 
out producing respiratory changes from the A Study of the Influence of Chloroform upon the 
14 
very first. In other words, we do not believe 
that in a healthy heart chloroform can cause 
serious disorder without, as a result of begin- 
ning disorder, disturbing respiration; and, 
second, that in a healthy heart a quantity of 
chloroform sufficient to disorder it will by its 
direct action disorder the respiration. If, as 
an extra precaution, one assistant watches the 
pulse while the other watches the respiration, 
very well, for though the respiration is the 
more important function to watch, the man 
watching the pulse might discover an irregu- 
larity which the ansesthetizer may not see re- 
produced in the respiratory action ; but as di- 
vided attention generally means a slighting of 
both objects in view, Lawrie is right in insist- 
ing on the pulse being let alone. 
In answer to Question 5 we have several 
points to offer: 
1. Hot climates (where ether is inapplicable), 
where a free circulation of air increases the 
safety of the patient. 
2. Chloroform may be used whenever a large 
number of persons are to be rapidly anaesthe- 
tized, so that the surgeon may pass on to 
others and save a majority of lives, even if the 
drug endangers a few, as on the battle-field, 
where only a small bulk of anaesthetics can be 
carried. 
3. Its employment is indicated in cases of 
Bright's disease requiring the surgeon's atten- 
tion, owing to the fact that anaesthesia may be 
obtained with so little chloroform that the kid- 
neys are not irritated, whereas ether, because 
of the large quantity necessarily used, would ir- 
ritate these organs. Quantity for quantity, 
ether is, of course, the less irritant of the two. 
4. In cases of aneurism, or great atheroma of 
the blood-vessels, where the shock of an opera- 
tion without anaesthesia would be a greater 
danger than the use of an anaesthetic, chloro- 
form is to be employed, since the greater 
struggles caused by ether and the stimulating 
effect which it has on the circulation and 
blood-pressure might cause vascular rupture. 
5. In children or adults who already have 
bronchitis, or who are known to bear ether 
badly, or, in other words, have an idiosyncrasy 
to that drug, chloroform may be employed. 
6. Persons who struggle violently, and who 
are robust and strong, are in greater danger 
from the use of chloroform than the sickly and 
weak, probably because the struggles strain the 
heart and tend to dilate its walls. 
The safest method of administration is by 
Lawrie's or inhaler, because these 
provide free circulation of air and do not dis- 
tract the attention of the ansesthetizer from 
the respiratory movement by complicated ap- 
paratus. Apparatus much like these, in allow- 
ing a free amount of air, are the Hyderabad 
chloroform inhaler or open-ended cone, with 
Krohne's and Seseman's respiration indicator 
attachment. 
The Junker inhaler, even with its modifica- 
tions, is too complicated and cumbersome, 
and while less chloroform is wasted in admin- 
istering the drug, it must all be thrown out 
of the bottle afterwards. If used at all, it 
should be used with the increased air-supply 
and respiration indicator of Krohne and Sese- 
man. 
We agree so heartily with Lawrie's personal 
conclusions that we print them below: 
1. The chloroform should be given on ab- 
sorbent cotton, stitched in an open cone or 
cap. (A depression made through the open- 
ing in the inside flannel bag will answer as 
well.) 
2. To insure regular breathing, the patient, 
lying down, with everything loose about the 
neck, heart, and abdomen, should be made 
to blow into the cone, held at a little dis- 
tance from the face. The right distance 
throughout the inhalation is the nearest which 
does not cause struggling or choking or hold- 
ing of the breath. Provided no choking or 
holding of the breath occurs, the cap should 
gradually be brought nearer to, and eventually 
may be held close over, the mouth and nose 
as insensibility deepens. 
3. The administrator's sole object while pro- 
ducing anaesthesia is to keep the breathing 
regular. As long as the breathing is regular, 
and the patient is not compelled to gasp in 
chloroform at an abnormal rate, there is ab- 
solutely no danger whatever in pushing the 
anaesthetic till full anaesthesia is produced. 
4. Irregularity of the breathing is generally 
caused by insufficient air, which makes the 
patient struggle or choke or hold his breath. 
There is little or no tendency to either of these 
untoward events if sufficient air is given with 
the chloroform. If they do occur, the cap 
must be removed, and the patient must be al- 
lowed to take a breath of fresh air before the 
administration is proceeded with. 
5. Full anaesthesia is estimated by insensi-' 
tiveness of the cornea. It is also indicated by 
stertorous breathing or by complete relaxation 
of the muscles. Directly the cornea becomes 
insensitive or the breathing becomes stertorous, 
the inhalation should be stopped. The breathing 
may become stertorous while the cornea is still 
sensitive. The rule to stop the inhalation 
should, notwithstanding, be rigidly enforced, Respiration and Circulation. 
15 
and it will be found that the cornea always 
becomes insensitive within a few seconds after- 
wards. 
It is only necessary to add that the patient 
should be so dressed for an operation that his 
respiratory movements can be easily seen by 
the chloroformist. In the climate of India 
this is not difficult to manage, but it is rather 
more so in the climate of Europe; so that in 
this respect, and in this respect alone, the 
chloroformist in England is placed at a distinct 
disadvantage compared with the chloroformist 
in India. 
Note.-Since writing this report two impor- 
tant papers upon this subject have appeared in 
the London Lancet,-the one by Gaskell and 
Shore, in which they carried out a complete line 
of ingenious cross-circulation experiments, and 
from which they conclude that the fall in blood- 
pressure seen under chloroform is due to car- 
diac rather than vaso-motor depression; and 
another paper, published by Lawrie, in the 
London Lancet for February n, 1893, in 
which he refutes the statements made by Gas- 
kell and Shore, and details experiments which 
he believes combat those of the two investiga- 
tors just named. 
We cannot help believing that cross-circu- 
lation experiments in regard to the action of 
chloroform must be received with considera- 
ble doubt by the practising physician. Even 
if such work is carried out with the greatest 
skill, the opportunities for error are innumer- 
able ; and while results are obtained which, 
if in accord with other studies, might be ac- 
cepted as confirmatory, the fact that they 
differ makes their negative conclusion of little 
value. 
The object of the investigator of the action 
of chloroform is to perform experiments which, 
so far as possible, will be counterparts of the 
employment of the drug for human beings. 
To the physiologist it is important to study • 
a drug in order that certain results may be ob- 
tained, whether they have practical bearing or 
not; but the practising physician only wishes 
those points which should guide him in the 
administration of the remedy. 
The concluding paragraph of Lawrie's latest 
contribution to the subject states the facts so 
clearly, and is so in accord with what we have 
tried to set forth in our own report, that we 
cannot do better than quote the paragraph : 
"The Hyderabad Commission's work proves 
that, while Syme's principles are right, there is 
no such thing as a safe method of chloroform 
administration. It is no longer a question of 
the superiority of the London method or of the 
Edinburgh method; absolute safety can be at- 
tained neither by watchipg the respiration nor 
the pulse for signs of danger, which are in 
either case proof of improper administration or 
of overdosing. Moreover, overdosing may 
take place whether the anaesthetic is given on 
lint or on a towel or on a cap such as we use, 
or with Junker's or Skinner's or any other 
form of apparatus. The all-important point is 
that the breathing shall never be interfered 
with in any way. Safety under chloroform 
can unquestionably be insured, but it can only 
be so by attending to regular natural breathing; 
and whatever method is employed, no one can 
deny that it is the bounden duty of the chloro- 
formist to maintain natural breathing through- 
out the whole period of administration. To 
maintain natural breathing requires careful 
training and considerable experience; but if 
these conditions be fulfilled it is impossible to 
produce anything with chloroform but anaes- 
thesia, and the Hyderabad Commission has 
shown that anaesthesia alone is entirely free 
from risk."* 
In reply to a general request for reports of 
cases of accident under chloroform, we received 
the answers shown in the appended table, 
which may be summarized as follows : 
Number of respiratory failures 29 
Number reported unable to feel pulse, 
while respiration continued 4 
Number of simultaneous failures I 
Number not stated 1 
Total number of accidents reported... 35 » 
Of the 29 respiratory failures there were 5 
deaths, a percentage of Of the 4 cir- 
culatory failures there were 2 deaths, a per- 
centage of 50. The 1 case of arrest of respira- 
tion and circulation simultaneously resulted in 
death. 
This summary is particularly interesting in 
that the great majority of accidents were due 
to respiratory failure and not to the heart, and 
this failure was irrespective of age, sex, condi- 
tion, or magnitude of operation ; also that the 
accident may occur before, during, or after the 
operation; and, finally, that in some instances 
circulatory failure takes place while respiration 
continues. 
* Provided the patient is in ordinary health. We 
would prefer to make the last sentence read, " Anaes- 
thesia can be safely produced by chloroform." (Hare 
and Thornton.) 16 
A Study of the Influence of Chloroform upon the 
Report of Accidents occurring during the Use of 
Name of reporter. 
Age. 
Sex. 
Operation. 
State of pa- 
tient at time 
of beginning 
anaesthetic. 
Kind of chlo- 
roform ad- 
ministered. 
Anaes- 
thetist. 
How ad- 
ministered. 
Rapidity of 
adminis- 
tration. 
Concen- 
tration of 
vapor. 
Length of time 
chloroform had 
been adminis- 
tered at time 
of accident. 
21 yrs. 
Male. 
Oblique inguinal 
hernia. 
Patient 
calm. 
Squibb's C. 
P. chloro- 
Skilled. 
On towel. 
Few drops 
at a time. 
Plenty of 
air. 
5 minutes. 
form. 
A. M. Haydem, 
Evansville, Ind. 
67 yrs. 
Male. 
Epithelioma of 
upper lip. 
Patient 
calm. 
Chloroform. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
H. S. Harrington, 
Bertrand, Neb. 
8 mos. 
Male. 
Talipes varus. 
Not stated. 
U. S. P. 
chloroform. 
Skilled. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
T. F. Hallett, 
Rose, N. Y. 
6 yrs. 
Male. 
Amputation of cut 
finger. 
Not stated. 
Quality of 
chloroform 
Skilled. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
not stated. 
W. H. Washburn, 
Milwaukee, Wis. 
45 yrs. 
Male. 
Renal colic. 
Not stated. 
Squibb's C. 
P. chloro- 
Skilled. 
On hand- 
kerchief. 
Few drops 
at a time. 
Plenty of 
air. 
Not stated. 
form. 
M. P. Murin, Den- 
9 yrs. 
Male. 
Tenotomy oftendo 
Not stated. 
Not stated. 
Unskilled 
Not stated. 
Pushed as 
Concen- 
Operation half 
ver, Col. 
Achillis and plan- 
tar fascia. 
intern. 
if it were 
ether. 
trated vapor 
of chloro- 
over; time not 
stated. 
form. 
M. P. Murin, Den- 
22 yrs. 
Male. 
Tight stricture; 
Patient 
Pure chloro- 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Operation 
ver, Col. 
internal urethrot- 
calm. 
form. 
over; exact 
omy. 
time it had 
been admin- 
istered not 
M. P. Murin, Den- 
45 yrs. 
Male. 
Stricture. 
Took drug 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
stated. 
Operation not 
ver, Col. 
badly. 
begun; time 
not stated. 
E. Lamphear, 
Kansas City. 
Not 
stated. 
Not 
stated. 
Cancer of pan- 
creas. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
A. W. Wilmarth, 
Norristown, Pa. 
16 yrs. 
Female. 
Epileptic convul- 
sions. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
C. T. Southworth, 
Monroe, Mich. 
Not 
stated. 
Not 
stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not Stated. 
C. T. Southworth, 
Not 
Not 
Not stated. 
Not stated. 
Not stated. 
Skilled. 
Esmarch 
Few drops 
Plenty of 
air. 
Operation 
Monroe, Mich. 
stated. 
stated. 
inhaler. 
at a time. 
nearly over; 
exact time 
C. D. Wescott. 
Not stated. 
not stated. 
16 yrs. 
Male. 
Sarcoma. 
JNot stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
No. i. 
3 yrs. 
Female. 
Harelip, cleft pal- 
ate. 
Not stated. 
J. H. Kellogg, Bat- 
tle Creek, Mich. 
24 yrs. 
Male. 
Left inguinal her- 
nia. 
Quiet. 
Chloroform 
supposedly 
pure. 
Not stated. 
Junker in- 
haler. 
Given care- 
fully. 
Not stated. 
Late; opera- 
tion almost 
completed. 
L. Reynolds, Hor- 
ton, Kan. 
28 yrs. 
Male. 
Enteralgia. 
Quiet. 
Squibb's C. 
P. chloro- 
form. 
Not stated. 
Handker- 
chief. 
Patient 
pulled drug 
over face 
Not stated. 
After a few 
moments. 
and mouth. 
5 yrs. 
Male. 
Crushed finger. 
Not stated. 
Not stated. 
Unskilled. 
Not stated. 
Given care- 
Not stated. 
Early in ad- 
fully. 
ministration. 
H. Mallens Wat- 
son, Norfolk, S. D. 
2 yrs. 
Male. 
Removal of can- 
cerous tentacle. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Given care- 
fully. 
Not stated. 
5 minutes. 
Robt. T. Morris, 
4 yrs. 
Male. 
Club-foot. 
Took drug 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Mew York. 
well up to 
time of full 
anaesthesia. 
Robt. T. Morris, 
30 yrs. 
Female. 
Dilatation of cer- 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Before opera- 
New York. 
vix. 
tion; time 
not stated. 
Robt. Morris, 
New York. 
35 yrs. 
Female. 
Straightening a 
flexed uterus. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
J. T. Webster, 
Emporia, Kan. 
4 yrs. 
Male. 
Paraphimosis. 
Not stated. 
Not stated. 
Unskilled. 
On cloth. 
Not stated. 
Not stated. 
Not stated. 
J. T. Webster, 
Emporia. Kan. 
Not 
stated. 
Male. 
Amputation of the 
thumb. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
J. N. Coons, Pal- 
Young 
Male. 
Removal of ne- 
Very weak 
Not stated. 
Skilled. 
Not stated. 
Not stated. 
Well diluted 
Not stated. 
myra, Mo. 
adult. 
crosed seques- 
trum of tibia. 
and ex- 
hausted. 
with air. 
J. P. Hachenberg, 
Austin, Texas. 
35 yrs. 
Female. 
Operation on foot. 
Not stated. 
Not stated. 
Skilled. 
Not stated. 
Not stated. 
Not stated. 
A few min- 
utes. 
G. W. Shidler, 
York, Neb. 
38 yrs. 
Male. 
Fistula in ano. 
Not stated. 
Not stated. 
Skilled. 
Not stated. 
Not stated. 
Not stated. 
Not stated. Respiration and Circulation. 
17 
Chloroform to produce General Ancesthesia. 
Quan- 
tity ad- 
minis- 
tered up 
to this 
time. 
First symptoms. 
State of 
patient 
at time 
of acci- 
dent. 
Respiration ceased first. 
Heart 
stopped 
first. 
Time of 
accident. 
Remarks. 
Treatment. 
Result. 
8 c.c. 
Patient suddenly 
Strug- 
Respiration ceased sev- 
Operation 
Inverted and ar- 
Death. 
of drug 
livid. 
gling. 
eral minutes before 
not begun. 
tificial respira- 
taken. 
heart stopped. 
tion. 
Not 
Suddenly respira- 
Not 
Both practically ceased 
Not stated. 
Has seen a number of non-fatal 
Inverted and ar- 
Death. 
stated. 
tion and pulse 
stated. 
at once. 
cases have respiratory failure, 
tificial respira- 
ceased. 
and resuscitated them. 
tion. 
Not 
Slight gasps given. 
Not 
Breathing stopped three 
Not stated. 
stated. 
stated. 
minutes; heart con- 
tinued to beat for this 
period after cessation 
of respiration. 
Not 
Patient stopped 
Not 
Breathing stopped; 
Not stated. 
Everything going well. Drug 
Inverted and ar- 
Recov- 
stated. 
breathing. 
stated. 
heart beating. 
withdrawn from 2 to 4 minutes 
tificial respira- 
ery. 
before accident occurred. 
tion. 
Not 
Respiration 
Not 
Respiration ceased, but 
No opera- 
After first recovery chloroform 
Artificial respi- 
Recov- 
stated. 
ceased. 
stated. 
pulse continued. 
tion. 
again given, and accident re- 
ration. 
ery. 
peated. 
Full 
Respiration 
Proba- 
Respiration ceased; 
Operation 
54 grain sulphate of morphine 
Artificial respi- 
Recov- 
quanti- 
ceased. 
bly not 
heart beating. 
half over. 
was given before anaesthetic 
ration for 25 
ery. 
ty;exact 
strug- 
was begun. 
minutes. 
amount 
not 
gling. 
stated. 
Not 
Face suddenly 
Quiet. 
Respiration ceased; 
Operation 
Respiration stopped, as bladder 
Artificial respi- 
Recov- 
stated. 
purple; eyes 
pulse strong. 
over. 
was distended with irrigation. 
ration, inver- 
ery. 
protruded. 
sion, nux vom- 
ica, belladon- 
na, whiskey. 
Not 
Spasm of muscles 
Strug- 
Respiration ceased; 
Operation 
All muscles of respiration very 
Inverted and ar- 
Recov- 
stated. 
of respiration; 
gling. 
pulse good. 
not begun. 
spastic. 
tificial respira- 
ery. 
Not 
respiration 
stopped. 
Respiration 
Not 
Respiration stopped; 
Operation 
Respiration stopped as finger 
tion. 
Artificial respi- 
Death. 
stated. 
stopped. 
stated. 
pulse good for 5 min- 
begun. 
touched diaphragm through an 
ration and 
utes. 
incision in belly. 
stimulation. 
Not 
Not stated. 
Not 
Respiration stopped be- 
Not stated. 
stated. 
stated. 
fore heart. 
Not 
Not stated. 
Not 
Respiration stopped be- 
Not stated. 
Operator and others noticed that 
Death. 
stated. 
stated. 
fore heart. 
pulse continued. 
Not 
Stopped breathing 
Quiet. 
Respiration stopped; 
Operation 
Operator and others noticed that 
Not stated. 
Death. 
stated. 
radial pulse good. 
over. 
pulse continued. 
Not 
Respiration 
Quiet. 
Respiration stopped, but 
Operation 
Artificial respi- 
Recov- 
stated, 
ceased. 
pulse full and strong. 
not yet 
ration and in- 
ery. 
but large 
begun. 
version. 
Artificial respi- 
Recov- 
ration and in- 
ery. 
version. 
Not 
Face assumed 
Not 
Heart 
Operation 
Particular attention paid to see 
Death. 
stated. 
livid color. 
stated. 
stopped; 
completed. 
which stopped first, heart or 
respiration 
continued 
* 
respiration. 
for a few 
moments. 
Not 
Respiration 
Not 
Respiration stopped; 
Artificial respi- 
Recov- 
stated. 
stopped. 
stated. 
heart strong. 
ration. 
ery. 
Not 
Pulse stopped; 
Not 
Pulse 
Operation 
Same occurrence three times in 
Artificial respi- 
Recov- 
stated. 
respiration la- 
stated. 
stopped; 
not com- 
same case before operation was 
ration and 
ery. 
bored. 
respiration 
pleted at 
completed. 
stimulation. 
labored. 
time of 
accident. 
Not 
Respiration 
Not 
Respiration ceased. 
Before op- 
The accident being repeated, no 
Artificial respi- 
Recov- 
stated. 
ceased. 
stated. 
eration. 
operation was done until next 
ration. 
ery. , 
day ; then under ether, without 
difficulty. 
t 
Not 
Stopped breathing 
Not 
Respiration ceased. 
Not stated. 
Not stated. 
Recov- 
stated 
stated 
ery. 
Not 
Cessation of res- 
Not 
Respiration ceased; 
Just before 
Not stated. 
Recov- 
stated 
piration. 
stated 
pulse good. 
I operation. 
ery. 
Not 
Stopped breathing 
Not 
Respiration ceased. 
Not stated. 
Not stated. 
Recov- 
stated 
stated 
Inverted and ar- 
ery. 
Not 
Stopped breathing 
Not 
Respiration ceased; 
Not stated. 
Recov- 
stated 
stated 
pulse continued good. 
tificial respira- 
ery. 
Not 
Stopped breathing 
Perfect 
Respiration ceased; 
During op- 
Inverted. 
Recov- 
stated 
lv limp. 
pulse full and regular. 
eration. 
Stimulated with 
ery. 
Not 
Pulse stopped for 
blot 
Pulse could 
Not stated. 
Thinks death would have re- 
Recov- 
stated 
at least r minute. 
stated 
not be felt. 
suited had he not closely 
ammonia, and 
ery. 
watched the pulse. 
fresh air ad- 
mitted to room 
Not 
Stopped breathing 
Deathly 
Respiration ceased. 
After opera- 
Attributes the accident to his al- 
Artificial respira 
Recov- 
stated 
pale. 
tion, and 
lowing patient to regain her 
tion and cold 
ery. 
patient 
feet too soon after operation. 
interrupted 
stood erect 
douche to 
chest. 
3 or 4 
Heart ceased to 
Not 
. Pulse conic 
Not stated. 
Patient had taken chloroform ten 
Artificial respi- 
Death. 
drachm 
beat. 
stated 
not be felt; 
years ago for extraction of 
ration. 
respiration 
continued 
tooth. 
for a min- 
ute longer. 18 
A Study of the Influence of Chloroform upon the 
Report of Accidents occurring during the Use of 
Name of reporter. 
Age. 
Sex. 
Operation. 
State of pa- 
tient at time 
of beginning 
antesthetic. 
Kind of chlo- 
roform ad- 
ministered. 
Anes- 
thetist. 
How ad- 
ministered. 
Rapidity of 
adminis- 
tration. 
Concen- 
tration of 
vapor. 
Length of time 
chloroform had 
been adminis- 
tered at time 
of accident. 
Louis J. Pons, 
Roxbury, Conn. 
25 yrs. 
Male. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
On napkin. 
Not stated. 
Not stated. 
Not stated. 
J. T. Baldwin, 
Columbus, 0. 
Elderly 
adult. 
Female. 
Removal of ure- 
thral caruncle. 
Not stated. 
Not stated. 
Young 
physician. 
Not stated. 
Not stated. 
Not stated. 
A few minutes. 
A. W. Wilmarth, 
Norristown, Pa. 
16 yrs. 
Not 
stated. 
No operation; 
given to quiet 
epileptic convul- 
sions. 
Struggling. 
Not stated. 
Skilled. 
Not stated. 
Not stated. 
Not stated. 
A few minutes. 
T. Walter Todd, 
Redondo Beach 
Not 
stated. 
Female. 
Not stated. 
blot stated. 
Not stated. 
Skilled. 
Not stated. 
Not stated. 
Not stated. 
A few minutes. 
Cal. 
Louis J. Pons, 
6 yrs. 
Male. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Not stated. 
Roxbury, Conn. 
Thos. R. Savage, 
New York. 
3° yrs- 
Female. 
Operation upon 
rectum. 
As the pa- 
tient was in- 
sane, it is 
probable 
she was 
not calm. 
Not stated. 
Not stated. 
Esmarch 
inhaler. 
Not stated. 
Admixture 
of air. 
Not stated. 
Thos. R. Savage, 
New York. 
24 yrs. 
Male. 
Removal of cathe- 
ter from bladder. 
Not stated. 
Not stated. 
.Not stated. 
Esmarch 
inhaler. 
Not stated. 
Admixture 
of air. 
Not stated. 
Thos. R. Savage, 
New York. 
47 yrs. 
Female. 
Carcinoma of 
breast. 
Not stated. 
Not stated. 
Not stated. 
Esmarch 
inhaler. 
Not stated. 
Admixture 
of air. 
Before anaes- 
thesia was 
complete. 
Thos. R. Savage, 
New York. 
7 days. 
Male. 
Spina bifida. 
Not stated. 
Not stated. 
Not stated. 
Esmarch 
inhaler. 
Not stated. 
Admixture 
of air. 
Not stated. Respiration and Circulation. 
19 
Chloroform to produce General Ancesthesia.-Continued. 
Quan- 
tity ad- 
minis- 
tered up 
to this 
time. 
First symptoms. 
State of 
patient 
at time 
of acci- 
dent. 
Respiration ceased first. 
Heart 
stopped 
first. 
Time of 
accident. 
Remarks. 
Treatment. 
Result. 
Not 
stated. 
Not stated. 
Not 
stated. 
Respiration ceased. 
Not stated. 
Artificial respi- 
ration ; hypo- 
dermic injec- 
Recov- 
ery. 
tion of ammo- 
Not 
stated. 
Respiration 
ceased and heart 
Not 
stated. 
Respiration; pulse good 
for some time. 
Not stated. 
nia. 
Artificial respi- 
ration. 
Death. 
feeble. 
Not 
stated. 
Respiration sud- 
denly stopped; 
pulse good. 
Not 
stated. 
Respiration ceased. 
Not stated. 
Artificial respi- 
ration. 
Recov- 
ery. 
Not 
stated. 
Respiration 
ceased. 
Not 
stated. 
Respiration ceased. 
Not stated. 
Same accident occurred twice in 
this operation. 
Artificial respi- 
ration. 
Recov- 
ery. 
Not 
stated. 
Not stated. 
Not 
stated. 
Respiration ceased. 
Not stated. 
Artificial- respi- 
ration ; hypo- 
dermic injection 
Recov- 
ery. 
Not 
Respiration 
Not 
Respiration ceased. 
Under full 
The same result was experienced 
ot ammonia. 
Artificial respi- 
ration and in- 
stated. 
ceased. 
stated. 
anaesthesia 
a month later in another opera- 
ery. 
during op- 
eration. 
tfon upon her. 
version. 
Not 
stated. 
Respiration 
ceased. 
Not 
stated. 
Respiration ceased. 
Under full 
anaesthesia 
Inversion and 
artificial respi- 
Recov- 
ery. 
during op- 
ration. 
Not 
Respiration 
Not 
Respiration ceased. 
eration. 
Before com- 
The accident reoccurred several 
Artificial respi- 
Recov- 
stated. 
ceased. 
stated. 
plete anaes- 
thesia. 
times, and as it was thought 
this was a case with idiosyn- 
crasy to chloroform, ether was 
ration. 
ery. 
substituted, with satisfactory 
result. 
Not 
Cyanosis and ar- 
Not 
Respiration ceased. 
During op- 
Inversion, and 
Recov- 
stated. 
rested respiratory 
movement. 
stated. 
eration. 
slaps upon back. 
ery. Experiment No. i. 
This tracing shows how the degression of pressure under chlorofcrm is only tempjrary and followed by a rise 
if chloroform is stopped for a moment. Slight rise seen in Part III. It also shows hew, if chloroform is pushed, 
respiration and circulation are hopelessly depressed, the respiration stopping first. 
Dog, weight twenty kilos. Chloroform given on towel closely applied to head. Twelve cubic centimetres 
of chloroform given in the two minutes preceding the beginning of this tracing. Struggling from first inhalation 
very slight. 
Tracing No. i-Continued. Part II. 
Without pause. 
Tracing No. i-Continued. Part III. 
No pause. Shows slight rise of pressure. 
Tracing No. i-Continued. Part IV. 
No pause. Tracing No. t-Continued. Part V. 
Ten seconds pause. 
Tracing No. i-Continued. Part VT 
No pause 
Tracing No. I (Wood and Hare) 
Tracing No. 2 (Wood and Hare). 
Tracing No. 3. Part I 
This tracing shows how artificial respiration causes a return of breathing and pressure. Respiration was stopped by 
ten cubic centimetres of ch'oroform, pushed rapidly. 
Dog, weight eight kilos. 
Tracing No. 3-Continued. Part II. Tracing No. 4. Part I. 
■BKflKSSMh 
9 
Shows that with anaesthesia there always ensues a fall ot arterial pressure. There is also a gradual failure of heart- 
force, as seen particularly in Parts VII. and VIII. in this tracing. 
Tracing No. 4-Continued. Part II. 
BTZS9 ■ 
No pause. 
Tracing No. 4-Continued. Part III. 
PfriiSS 
No pause. Tracing No. 4-Continued. Part IV. 
No pause. 
Tracing No. 4- Continued. . Part V; 
No pause. 
Tracing No. 4- Continued. Part VI» 
No pause. Tracing No. 4- Continued* Part VII. 
No pause. 
Tracing No. 4-Continued. Part VIII. 
No pause. 
Tracing No. 5. Part I. 
Weight ten kilos. Chloroform given on Esmarch inhaler to the amount ot twenty cubic centimetres in 
preceding ten minutes. Artificial respiration instituted as soon as voluntary respiration ceased at first X markj 
failed to restore respiration and to preserve circulation. See Part II. of this tracing. Tracing No. 5-Continued. Part II. 
.■ ' 
Respiration stopped at first X mark. 
Tracing No. 5-Continued. Part III. 
Tracing No. 8. Part I. 
Tracing No. 8-Continued. Part IL 
No pause. 
Tracing No. 8-Continued. Part III. 
No pauset Tracing No. 8-Continued. Part IV. 
Two m'nutes finee Part III. 
Tracing No. 8-Continzied. Part V. 
No pause. 
Tracing No. io. Part I. 
This tracing shows how, if chloroform is pressed, the respiration finally ceases, and the circulation is persistently de- 
pressed ; also, that atropine prevents a rapid fall of pressure. 
H 
Tracing No. io-Continued. Part IT Tracing No. io-Continued. Part III. 
Tracing No. io-Continued, Part IV. 
Tracing No. io-Continued. Part V, 
A pause of one and one-half minutes between this part and Part IV. Tracing No. ic-Continued. Part VI. 
kiJM 
Tracing No. io- Continued. Part VII. 
Tracing No. io-Continued. Part VIII. 
' ' SBrafir 
No pause. 
Tracing No. io-Continued. Part IX. 
No'pause. Tracing No. io-Continued. Part X. 
MEfjlMgJM- 
Two minutes' pause in changing drum. 
Tracing No. io-Continued. Part XI. 
No pause. 
Tracing No. io-Continued. Part XII. 
B/jmEH 
No pause. 
Tracing No. io-Continued. Part XTII. 
No pause. Tracing No. io-Continued. Part XIV. 
[BBWWpWw 
WKwWnwi 
No pause 
This tracing shows how the pulse and respiration may apparently cease finally, yet return after some moments, and 
then fail again, the respiration stopping first, the heart finally being in good condition. See Part V. 
Tracing No. 12. Part I. 
Br/HPwS 
F<1 
Dog, weight ten kilos. Four cubic centimetres of chloroform given thirty seconds before this tracing begins 
Tracing No. 12-Continued. Part II. 
No pause. 
Tracing No. 12-Continued. Part ITT. 
No pause. Tracing No. 12-Continued. Part IV. 
No pause. 
Tracing No. 12-Continued. Part V. 
No pause. 
This tracing shows characteristic fall of blood-pressure under chloroform, the irregular pulse due to struggling, 
and the effect of primary irritation of the vagal and trigeminal nerves. It also shows how, when the arterial pressure 
and heart-action seem practically nil, recovery of both may occur, if the chloroform is not pushed. Also recovery of 
respiration voluntarily. (See Parts VI., VII., XL, and XIV. of this experiment.) Also shows how, when chloro- 
form is pushed, there comes a time when respiration ceases finally and pressure falls very low. (See Parts XV. and 
XVI.) As usual, respiration ceased before heart. 
Tracing No. 13. Part I. 
BBS 
-Dog, weight six kilos. Struggling began before chloroform was given, as marked on paper. 
Tracing No 13-Continued. Part IT. 
- '•? ':> Xs-'■ Tracing No. 13-Continued. Part III. 
No pause. 
Tracing No. 13-Continued. Part IV. 
No pause. 
Tracing No. vt,-Continued. Part V. 
No pause. Tracing No. 13-Continued. Part VI. 
';v 
A pause of twenty seconds, owing to pen getting caught in thread. During this pause pen fell to point shown in 
very beginning of this tracing. 
Tracing No. 13-Continued. Part VII. 
Tracing No. 13-Continued. Part VIII. 
No pause. 
Tracing No. 13-Continued. Part IX. 
No pause. Tracing No. 13-Continued. Part X. 
Beginning of another paper on second drum. About forty seconds lost in removing first drum and placing second 
drum in place. Shows complete restoration of blood-pressure. 
Tracing No. 13-Continued. Part XI. 
No pause. 
Tracing No. 13-Continued. Part XII. 
No pause. Tracing No. 13-Continued. Part XIII. 
No pause. 
Tracing No. 13- Continued. Part XIV. 
No pause. 
Tracing No. 13-Continued. Part XV. 
No pause. 
Tracing No. 13-Continued. Part XVI. 
No pause. This tracing shows that an animal apparently dead from cardiac failure caused by chloroform has a temporary return 
of heart-action. 
Tracing No. 14. Part I. 
Dog, weight six kilos. Four cubic centimetres of chloroform injected into jugular. 
Tracing No. 14-Continued. Part II. 
No pause. 
Tracing No. 14-Continued. Part III. 
M 
■JtWB 
Thirty seconds' pause. 
Tracing No. 15. Part I. 
- 
Chloroform in concentrated vapor from towel tightly around head. Tracing No. 15-Continued. Part II. 
tfjLWH 
No pause. 
Tracing No. 16. Part I. 
This tracing shows that chloroform, even when given very freely in four cubic centimetre doses, does not lower 
blood-pressure as rapidly when atropine is given as when it is not. It also shows how, when chloroform is pushed, the 
respiration finally ceases and the pressure falls lower and lower. See Parts X., XI., and XII. 
Tracing No. 16-Continued. Part II. 
No pause. Tracing No. 16-Continued. Part III. 
No pause. 
Tracing No. 16-Continued. Part IV. 
IrjBitMbl 
No pause. 
Tracing No. 16-Continued. Part V. 
No pause. Tracing No. 16-Continued. Part VI. 
No pause. 
Tracing No. 16-Continued. Part VII. 
No pause. 
Tracing No. 16-Continued. Part VIII. Tracing No. 16-Continued. Part IX. 
Tracing No. 16-Continued. Part X. 
'<<<c ? ;*■' . ■ ' ' ■ fcl 
No pause. 
Tracing No. 16-Continued. Part XI. 
No pause. 
Tracing No. 16-Continued. Part XII. 
No pause. The section of the vagi was made to see if any effect would result, and not because it was thought these 
nerves were stimulated. Tracing No. 17. Part I. 
This tracing shows how chloroform may so depress the circulation as to make one think the animal is dead, but 
the heart, if given time, regains its action. (See Parts IX., X., and XI.) It also shows how, if chloroform is pushed, 
the respiration stops and the pressure falls (see Parts XIII., XIV., XV., and XVI.), and that the respiration may 
begin spontaneously as the pressure rises. (See Parts X. and XIII.) 
Tracing No. 17-Continued. Part II. 
No pause. 
Tracing No. 17-Continued. Part III. 
No pause. 
Tracing No. 17-Continued. Part IV. 
No pause. Tracing No. 17-Continued. Part V. 
HEmH 
HMfSgmSM 
KhlS| 
Pause of twenty seconds. 
Tracing No. 17-Continued. Part VI. 
IWiJtagslSsSl 
JEa 
No pause. 
Tracing No. 17-Continued. Part VII. 
E3 
No pause. 
Tracing No. 17-Continued. Part VIII. 
No pause. Tracing No. 17-Continued. Part IX. 
Tracing No. 17-Continued. Part X. 
Kh 
Four minutes lost in changing drum. During this time no chloroform was given. Tracing shows recovery 
of blood-pressure. Respiration returned during pause. 
Tracing No. 17-Continued. Part XI 
No pause. 
Tracing No. 17-Continued. Part XII. 
No pause. Tracing No. 17-Continued. Part XIII. 
No pause. 
Tracing No. 17-Continued. Part XIV. 
Tracing No. 17-Continued. Part XV. 
No pause. 
No pause. 
Tracing No. 17-Continued. Part XVI. 
' X3M ■ 
No pause. 
This tracing shows very long circulatory maintenance when atropine is given. It also shows how, when chloroform 
is pushed, it finally causes arrest of respiration and fall of pressure. 
Tracing No. 18. Part I. 
wtwwi 
Dog, weight seven kilos. This is beginning of second drum. During first drum (ten minutes) he had received 
grain of atropine and two drachms (eight cubic centimetres) ,of chloroform eyery minute, or eighty cubic centi- 
metres. As this first drum-tracing is a counterpart of No. 17, it is not given. Tracing No. 18- Continued. Part II. 
MtJlEA 
No pause. 
Tracing No. 18-Continued. Part III. 
No pause. 
Tracing No. 18-Continued. Part IV. 
No pause. 
Tracing No. 18-Contintied. Part V 
No pause. 
Tracing No. 18-Contintied. Part VI. 
No pause. 
Tracing No. 18-Continued. Part VII. 
[Plate lost by maker of plates.-Showed no change except gradual fall of pressure.] 
No pause. Tracing No. 18-Continued. Part VIII. 
No pause. 
Tracing No. 18-Continued. Part IX. 
SMg 
S8jj 
No pause. 
Tracing No. 19. Part I. 
Dog, weight twelve kilos. This shows tracing before chloroform was used. 
Tracing No. 19-Continued. Part II. 
BBSS 
A pause of three minutes since last tracing to fix pen, which was out of order. Tracing No. 19-Continued. Part III. 
No pause. 
Tracing No. 20. Part I. 
WMKE1 
Tracing No. 20-Continued Part II. 
No pause. 
Tracing No. 20-Continued. Part III. 
■M^f* j 
• . •„ ' 
HrjKs 
No pause. Tracing No. 2c-Continued. Part IV. 
No pause. 
Tracing No. 20-Continued. Part V. 
No pause. 
Tracing No. 20-Continued. Part VI. 
No pause. 
Tracing No. 21. Part I. 
This tracing shows arrest of heart by injecting chloroform into the left ventricle, and that the right continues to beat 
though the left stops. (See Part VII.) 
BS0WS 
Dog, weight twelve and a half kilos. 
Tracing No. 21-Continued. Part IT. 
No pause. Tracing No. 21-Continued. Part III. 
No pause. 
Tracing No. 21-Continued. Part IV. 
No pause. 
Tracing No. 21-Continued. Part V. 
No pause. 
Tracing No. 21-Continued. Part VI. 
No pause. 
Tracing No. 21-Continued. Part VII. 
mrimliiii imiwMMliM'iOffiiiiiii i iBim : H^Tmir 
No pause.  
MM 
ffiHMMMMM 
Tracing No. 22-Continued. Part II. 
For explanation, read text and tracing, Part I. 
Vagi cut before chloroform was given. 
Tracing No. 22. Part I. ' 
No pause. 
QjHNgm H 
Qgggg 
H 
£1 
Ejj 
grown 
1 
H 
Tracing No. 22-Continued. Part III. 
Tracing No. 22-Continued. Part IV. 
No pause. 
No pause. Tracing No. 23. Part I. 
This tracing shows how chloroform depresses the circulation, but that the pressure very soon rises as the animal 
frees itself from the drug. (See Part IX.) It also shows how, if chloroform is pushed, respiration ceases and the 
pressure falls. (See Parts XII., XIII., XIV., XV., and XVI.) See interesting rise of pressure in Parts XVII. and 
XVIII. 
Tracing No. 23-Continued. Part II. 
No pause 
Tracing No. 23-Continued. Part III 
No pause. Tracing No. 23-Continued. Part IV. 
No pause. 
Tracing No. 23-Continued. Part V. 
No pause. 
Tracing No. 23-Continued. Part VI. 
No pause. Tracing No. 23-Continued. Part VII. 
No pause. 
Tracing No. 23-Continued. Part VIII. 
- 
... 
No pause. 
Tracing No. 23-Continued. Part IX. 
EEMEiMBESM 
No pause. Tracing No. 23-Continued. Part X. 
[Si i " riMBaamM 
Wr Jr - itS 
- - MyWjMBB " 
No pause. 
Tracing No. 23-Continued. Part XI. 
[Tracing lost by maker of plates.] 
Chloroform given. Two minutes lost in changing drum. 
Tracing No. 23-Continued. Part XII. 
No pause. Tracing No. 23-Continued. Part XIII. 
No pause. 
Tracing No. 23- Continued. Part XIV. 
No pause. 
Tracing No. 23-Continued. Part XV. 
No pause. Heart maintains same pressure in vessels, though very feeble and apparently stopped so far as pulse work 
is concerned. 
Tracing No. 23-Continued. Part XVI. 
No pause. This shows the same as Part XV.  
Tracing No. 23-Continued. Part XVII. 
Tracing No. 23-Continued. Part XVIII. 
No pause. 
No pause. This tracing shows how chloroform, when in contact with the heart, acts as a direct depressing poison. 
Tracing No. 24. Part I. 
Dog, weight six and a half kilos. Full-grown bitch. No chloroform until after vagal section. 
Tracing No. 24-Continued. Part II. 
MBHDRKvHBK&fl 
EmhSS 
No pause. 
Tracing No. 24-Continued. Part III. 
No pause. 
< Sv 
Tracing No. 24-Continued. Part IV. 
No pause. 
Tracing No. 24-Continued. Part V. 
fWKEQ 
"No pause. This tracing shows how chloroform paralyzes the heart-muscles when it comes in direct contact with it after injection into right ventricle. (See Part II.) Also, that the heart stops independently of any vagal action. 
■ .. 
By 
S3 
Dog, weight eight and a half kilos. Vagi cut before chloroform used. 
S3 
Tracing No. 25-Continued. Part II. 
Tracing No. 25. Part I. 
No pause. 
LS Tracing No. 26. Part I. 
This tracing shows slight fall of pressure, stoppage of respiration, and spontaneous'jrenewal of respiration. 
Dog, weight twenty pounds. Four cubic centimetres of chloroform given on towel tightly applied to head. 
-Tracing No. 26-Continued. Part II 
No pause. 
This tracing shows how artificial respiration, resorted to at the proper time, may result in recovery of respiration'jand 
circulation. 
Tracing No. 27. Part I. 
Dog, weight twenty kilos. Chloroform on towel tightly about head. Shows fall of blood-pressure. Arrest of 
respiration at X mark on next section of tracing. Tracing No. 27-Continued. Part II. 
No pause. Respiration stopped at second X mark. 
Tracing No. 27-Continued. Part III. 
Ten seconds' pause. 
Tracing No. 27-Continued. Part IV. 
No pause. 
Tracing No. 27-Continued. Part V. 
Two minutes later.