363 INFLUENCE OF THE BRAIW ON THE ACTION OP THE HEART, 



E;£p. 3. On a Exp, 3. The experiment was **epeated on a rabbit. The 



rabbit. Action temperature of the room war60«'. The respirations were 

 of the heart. , - . . „. 



made from 30 to 35 m a minute. The actions of the heart 



at first were strong and frequent: but at the end of one 

 hour 40 minutes the pulse had fallen to 24 in a minute. 

 BIoocL The blood in the arteries was seen of a florid red, and 



that in the yeins of a dark colour. 



A small opening was made in the abdominal muscles, 

 through which the thermometer was introduced iiito the 

 abdomen, and allowed to remain among the Tisoera. 

 Animal heat. At the end of an hour the heat in the abdomen had fallen 

 from 100° to 89"^, At the end of an hour and forty mi- 

 nutes in the same situation the heat had fallen to 85°, and 

 when the bulb of the thermometer was placed in the thorax 

 in contact with the lungs the mercury fell to 82°. 

 Seemingly not It has been a very generally received opinion, that the 

 de,-^endent on |jg^^ q£ warm blooded animals is dependent on the chemical 

 chemical ,,,,,,. 



changes of the Changes produced on the blood by the air m respiration. 

 Wood in respi- jf, tjjg ^y^Q j^st experiments the animals cooled tery rapidly, 

 notwithstanding the blood appeared to undergo the usual 

 changes in the lungs ; and I was therefore induced to doubt 

 whether the above mentioned opinion respecting the source 

 of animal heat is correct. No positive conclusions hovv, 

 ever could be deduced from these experiments. If animal 

 heat depends on the changes produced on the blood by 

 the air in respiration, its being kept up to the natural 

 standard, or otherwise, must depend on the quantity of 

 air inspired, and on the quantity of blood passing through 

 the lungs in a given space of time: in other words, it must 

 be in proportion to the fulness and frequency of the pulse, 

 and the fulness and frequency of the inspirations. Ifc 

 therefore became necessary to pay particular attention ta 

 these circumstances. 

 Exp« 4. On a Exp. 4. The experiment was repeated on a dog of a small 

 small dog. gj^^^ whose pulse was from 130 to 140 in a minute, and 

 whose respirations, as far as I could judge, were perform^, 

 ed from 30 to 35 times in a minute. 



The temperature of the room was 63^. The heat in the 

 rectum of the animal at the commencement of the experi. 



ment 



