ANIMAL HEAT. 



523 



apparatus of the body: the polypnoeic, the sudorific ,and the vaso- 

 motor centers. 



Polypnwa. Professor Eichet found that with the elevation of 

 the body-heat of an animal its respirations suddenly increased to 

 350 or 400 per minute. This form of respiration he termed polyp- 

 mra. It was found that the animal did not do this from want of 

 oxygen. An animal pants to cool himself, while a man perspires 

 for the same purpose. The role of polypnoea is exclusively to reg- 

 ulate the temperature of the body. 



I have made numerous experiments to determine the exact seat 

 of the polypnceic center. To establish a center three things are 

 necessary : (1) that its abolition causes the phenomena to disappear, 



Fig. 186. Curve of Temperature and Respiration when the Tuber 

 Cinereum is Destroyed and the Animal is Artificially Heated. 



(2) that irritation mechanical, chemical, or electrical causes the 

 phenomena to be present, and (3) that the part of the nervous sys- 

 tem exhibiting these peculiarities be circumscribed in extent. After 

 lumerous observations and experiments it was found that pressure 

 ipon the tuber cinereum with a pledget of cotton, or even slight 

 juncture, increased the normal respirations to the point of polypnoea. 

 Complete puncture in a normal animal was followed by a rise to 

 .06 F. within two hours, even though the animal was bound down 

 ind had been subjected to considerable shock. 



If now the animal whose tuber is punctured be heated, there 

 T ill result no polypnoea, even though a temperature of 107 F. be 

 Cached. I am convinced that the tuber cinereum is a center of polyp- 



