389 



at the end of two hours it had fallen 14 in the thorax ; and at the 

 end of the experiment 20 in the thorax. 



At the beginning of this experiment the ureters had been tied ; 

 and at the end of the experiment it was found that no urine was col- 

 lected above the ligature. 



The third experiment was made upon a rabbit ; and the artificial 

 respiration was continued one hour and forty minutes. A thermo- 

 meter in the cavity of the abdomen fell in the first hour from 100 to 

 89 ; and in the next forty minutes to 85 ; but in the cavity of the 

 thorax it was as low as 82. 



Since the blood in these experiments was observed to retain its 

 florid red colour in the arteries, it might be expected, according to the 

 common theory of animal heat, to retain also its proper temperature; 

 but Mr. JBrodie observes, that this must also depend on the fulness 

 and frequency of the pulse, together with the fulness and frequency 

 of inspiration. It therefore became necessary to attend particularly 

 to these circumstances. 



In the fourth experiment, which was also made upon a rabbit, the 

 natural inspirations were imitated as nearly as possible ; and at the 

 end of forty minutes the pulse was found to continue as high as 1 40 

 in a minute, but the heat had declined from 99 to 92|. At the end 

 of one hour and twenty-five minutes, a thermometer in the pericar- 

 dium was 85, in the abdomen 87. 



In the fifth experiment the pulse continued at 140 for upwards of 

 an hour, but the heat in the rectum declined from 101^ to 92. 



In a subsequent experiment two rabbits were chosen, as nearly 

 alike in size and every particular as possible. Both were killed ; but 

 one was suffered to cool gradually without interruption ; and in the 

 other the circulation was continued by means of artificial respiration. 



At the beginning of the experiment the temperature of each was 99. 



At the end of half an hour that of the former was 99 ; the latter 97 



Three quarters of an hour 98 - 95| 



One hour 96| 94 



One hour and a half 94 91 



It appeared, therefore, that respiration tended rather to cool than 

 to support the animal heat. But since it was possible that a small 

 portion of heat might be generated, but counteracted by the contact 

 of cold air, a subsequent experiment was made, in which the large 

 vessels of the heart Avere tied, so as to prevent any circulation of the 

 blood ; and in this case the heat remained comparatively greater than 

 in the former, as the cooling effect of the air was not diffused to 

 distant parts of the body. 



From the whole the author concludes, 



1st. That the influence of the brain is not directly necessary to the 

 action of the heart. 



2nd. That the interruption of the circulation is owing to the stop- 

 page of respiration. 



