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to a careful and thorough re-study of the subject. Some of our experiments were made by
injecting chloroform into the jugular vein; others by administering it by inhalation in the
usual way.
The action of the chloroform seems to be not seriously modified by the method of
administration. We definitely proved that in the dog chloroform has a distinct, direct, para-
- l y s i n g i n f l u e n c e o n b o t h r e s p i r a t i o n a n d c i r c u l a t i o n ; t h a t t h e r e s p i r a t i o n m a y c e a s e b e f o r e t h e
heart beat, or the two functions be simultaneously abolished; but that in some cases the heart
is arrested before respiration. We have several times seen the respiration continues as long
as one, and even two minutes after the blood-pressure has fallen to zero, and the pulse has
completely disappeared from the carotid artery.
The correctness of our experiments, we claim, must be acknowledged. The experiments
have not only been witnessed by a number of persons, but I have with me to-day tracings
which I will gladly show any one especially interested in the subject. I do not desire to
express any doubt whatever as to the correctness of the experimental data of Dr. Brunton; I
simply claim that both sets of experiments, although they have yielded different results, have
been correctly and properly performed. It may be that the high heat or other climatic
conditions surrounding the pariah dog make his heart less sensitive to the action of chloroform
than is the heart of the dog bred in northern climates. That the thought of the different
c o n s t i t u t i o n s o f a n i ma l s i n d i f f e r e n t c l i ma t e s i s n o t a b s u r d , i s s h o wn b y t h e f a c t t h a t s o me y e a r s
a g o —a f t e r I h a d a f f i r m e d b e f o r e t h e P h y s i o l o g i c a l S e c t i o n o f t h e I n t e r n a t i o n a l Me d i c a l
Congress at London, that if certain asserted results were obtained upon European dogs, said
dogs must differ from those of America, and had been met with a smile of incredulity—Dr.
Brown Sequard rose and stated that he had experimented upon hundreds of dogs on both
continents, and that there was a distinct difference between the animals the vascular system of
the European dogs being much more developed, and operations upon them being, therefore,
much more bloody than was the case with the American dog.
A very curious parallel might be traced at this point, between the experimental and
clinical evidence in regard to the effect of climate upon the action of chloroform. In the
Southern United States chloroform is used with great freedom, and with great alleged safety;
and as long ago as 1878 Dr. Langdon B. Edwards, editor of theV i r g i n i a M e d i c a l M o n t h l y ,
w r o t e : " I t i s o n e o f t h e m o s t p e c u l i a r e f f e c t s I h a v e e v e r k n o w n i n m e d i c a l p r a c t i c e — t h e
difference of experience in Europe and the North with chloroform and ether as compared with
that of the South—the high rate of mortality in the North, and the low rate in the South."
Further, in a recent letter to me Sir Joseph Fayrer affirmed the extraordinary safety of
c h l o r o f o r m i n I n d i a , a n d s t a t e d t h a t h e k n e w o f n o d e a t h f r o m i t a s h a v i n g o c c u r r e d i n t h a t
country, although its use is universal.
In a series of experiments which I have recently made myself to determine the changes
in the circulation produced when ether anæsthesia is carried on to death. I have found that in
the first periods of anæsthesia the blood-pressure is usually elevated, and that it is usually
quite high at a time when the respirations are very shallow and imperfect, and the dark
colour of the blood shows that it is heavily charged with carbonic acid. It is not, however,