184 THE LAWS OF ORGANIC 



tigated by several distinguished physiologists 

 since the time of CRAWFORD, and it seems now to 

 be generally believed, that the arterial has a tem- 

 perature of one or two degrees superior to that of 

 the venous blood. This opinion militates very 

 much against the one brought forward by CRAW- 

 FORD, and may be said to destroy the consistency 

 of his theory. 



CCIV. The body was supposed, by CRAWFORD, 

 to possess a uniformity of temperature at the va- 

 rious seasons of the year, and throughout the 

 whole system. The former condition was re- 

 garded as arising from the less perfect changes of 

 the vital fluid in the capillary vessels, in conse- 

 quence of which the quantity of inflammable 

 matter brought by the veins to the lungs was di- 

 minished ; and as he believed the evolution of 

 animal heat to be proportionate to the chemical 

 changes between the inspired air and this inflam- 

 mable matter, it followed, from his doctrine, that 

 less heat would be generated in summer, when the 

 necessities were less, and more in winter, when 

 they are greater. In cxcvni. and cxcix. I 

 have shewn the fallacy of those premises by which 

 he was led to draw this conclusion. The equality 

 of temperature throughout the system naturally 

 flowed from his principles, which supposed ani- 

 mal heat to be given out by the blood in imbib- 

 ing the phlogistic principle from the capillaries. 



