42 



of its own ; it would, on the contrary, by such a 

 source, be constantly kept at a much higher tem- 

 perature, than the mammalia in general have. 

 This circumstance is, of course, decisive against 

 the change of the colouring matter in the placenta, 

 although we must confess, that the stay of the 

 blood there must answer some important purpose. 

 FOURCROY has communicated some observa- 

 tions on the blood of the foetus; but they seem 

 to bave been made by chance, and not to be de- 

 duced from any experiments, 



- * ' -_ , f " * 



The dissimilarity of the blood in certain diseases 

 was examined by DEYJEUX and PARMENTIER, 

 and the result of their examination was, that the 

 difference from the healthy state was so inconsi- 

 derable, that in the state of the science at that 

 time, they were hardly to be ascertained. Du-r 

 PUYTREN, THENARB and NICOLAS, have made 

 experiments with diabetic blood, and proved, 

 that not the smallest portion of the sugar, which 

 is so abundantly found in the urine of those afr 

 flicted with diabetes, can be discovered in the 

 blood. 



What I have here stated concerning the blood 

 and respiration, relates chiefly to man. We have 



