56 Ammalcules in Snow. 



Notwithstanding the experiments of Mr. Brodie, it appears to be 

 allowed that at least a portion of animal heat is derived from the for- 

 mation of carbonic acid during respiration, in the manner suggested 

 by Dr. Crawford. But according to the most accurate experiments 

 only a part of the heat is accounted for in this manner. The remain- 

 der has been ascribed to various causes, as the processes of nutrition 

 and secretion, and even to the friction of the different parts of the 

 body upon each other. But it occurs to me that if the views here 

 advanced are correct, we need not look elsewhere to account for the 

 additional quantity of heat. If cyanogen is formed in the course of 

 the circulation and united with iron, a portion of heat must in this 

 way also be generated; — -and thus the whole might be placed to the 

 account of respiration alone. 



These are the facts and reasonings which have induced me with 

 some confidence to advance the opinion that during respiration the 

 nitrogen of the air is absorbed by the blood ; — that it combines tvith 

 the carbon in the blood ; — that the cyanogen thus formed unites with 

 iron ; and that cyanide of iron is therefore, one of the constituents 

 of that fluid. If this is admitted, the formation of hydrocyanate of 

 iron could be easily shown, and perhaps the study of this would lead 

 to more correct notions concerning the difference between venous 

 and arterial blood, especially as it regards color. But fearing that 

 I may already have trespassed the precepts of the Baconian philoso- 

 phy, I forbear pursuing the subject at present. 



Albany, N. Y. July, 1830. 



Art. V in. — Notice of Animalcules in Snow; in a letter to the 

 Editor, from Dr. Joseph E. Muse. 



Dear Sir — I believe it is universally admitted, that in the wide, or 

 rather unlimited, range of the natural sciences, nothing has attracted 

 the attention and inquiry of man, more anxiously, than the mysteries 

 of " animal life." The circumstances under which it is occasionally 

 observed to be supported, in repugnance to our common experience 

 and limited knowledge, are worthy to be recorded ; and though appa- 

 rently trivial in themselves, yet when accumulated, arranged, and 

 appropriately digested, they may, by their concurrent influence, 

 throw new light upon this interesting branch of physiology, which is 

 now enveloped in much darkness. 



