178 REPORT— 1868. 
Influence on the Animal Temperature. 
A subject of much importance seemed to me to be open for inquiry in 
respect to the conditions of the animal temperature under the action of those 
methyl and ethyl compounds which produce temporary insensibility. At- 
tempts had already been made by myself and others to determine the order 
of facts from the human subject. But the circumstances under which the 
narcotizing agents are administered to human kind are so peculiar that 
no separate observer could conduct a satisfactory research in a sufficient 
number of cases to be reliable. To arrive at correct data, a period of three 
hours at least is required for each observation; the air of the room in which 
the observation is made must be kept at a steady and uniform heat; three 
observers are also wanted, and the utmost quiet must prevail, that excite- 
ment of an external character do not move or annoy the suvject. To meet 
these necessities, I determined to conduct the research on inferior animals. 
T selected from two kinds of animals,—the guineapig, whose temperature is 
not more than two degrees above man, and the pigeon, an animal which has 
a mean temperature full ten degrees above that of man. I next selected 
chloroform and ether as the two agents to be tested ; it was necessary, from 
the labour and time demanded, not to take more than two substances, and 
these I considered were fair representatives of two distinct series, while at 
the same time they were substances with which the world of science generally 
is most familiar. 
I had the pleasure of being most ably assisted in observation by my 
friends Dr. F. Versmann and Dr. Sedgwick, with Mr. Alfred Nutt occasionally, 
and Mr. Alfred Haviland ; in every case another pair of eyes besides my own 
kept strict watch. The thermometers used were by Casella. The plan of 
proceeding was first to bring the air of the laboratory to a fixed temperature, 
the mean of 54° Fahr. being carefully sustained. In this air the animal was 
allowed to live for two hours before the observation, and the natural tempe- 
rature of the animal was carefully noted—in the pigeon from the cloaca, in 
the guineapig from the rectum. 
The animals were put to sleep by being made gently to inhale the vapours 
to which they were subjected from a mask covered with thin flannel, and the 
thermometer was watched and registered through every stage of narcotism, 
and for one hour or more after recovery. 
In one pigeon the observation was conducted three separate times, in 
another pigeon twice, and in five other pigeons once. Tn one guineapig the 
observation was made three times, in another twice, and in five others once. — 
The phenomena were amongst the most uniform I have ever recorded in | 
experiment. 
In the pigeons subjected to chloroform there was in every case a fallinthe © 
thermometer, during the narcotism, of from 6°°5 to 6° Fahr. This was so 
singularly correct that the result actually varied with the natural tempe- — 
ratures of the birds. Thus in one of the birds, in which the natural tempe- — 
rature was 107°°5, the thermometer came down regularly to 101°; while in — 
another bird, the natural temperature of which was 110°, the thermometer — 
regularly fell to 104°. : 
This decline in temperature did not date from the actual commencement — 
of inhalation. For the first stage the thermometer remained steady; as the © 
second stage advanced it rose on an average half a degree, to sink at once as 
the excitement passed away ; while as the third stage was reached (with en- | 
tire loss of sensation and of motion) it fell from three to four degrees, As the j 
third stage became more determined, and the fourth approached, the decline 
