DIGESTION. 511 



the observations of Pallas, Muller, Treviranus, 

 Rudolphi, and many others. But caloric is no 

 less essential to fermentation, germination, circu- 

 lation, nutrition, or the generation of microscopic 

 plants and animals from the proximate consti- 

 tuents of dead organic matter, than to the combi- 

 nations of ordinary chemistry. 



So far as digestion depends on the solvent 

 power of gastric juice, it is a chemical process, 

 by which dead matter is converted into chyme. 

 And that it is owing chiefly to the agency of 

 caloric, would appear from the fact, that the 

 digestive function in all animals is performed 

 with a rapidity exactly in proportion to their 

 mean healthy temperature, being greater in birds 

 than in mammalia, and very much greater in 

 both than in cold blooded animals, which require 

 many days, and some of them several weeks to 

 digest a single meal. We also learn from the 

 experiments of Spallanzani, that the solvent 

 power of gastric juice when taken from the sto- 

 mach increases from 50 to 120 F. ; and from the 

 late researches of Dr. Beaumont, that when put 

 in vials and kept at the temperature of 100, it 

 converted food into a species of chyme that could 

 scarcely be distinguished from what was formed 

 in the stomach, but required a longer time to pro- 

 duce the effect. The fact is, that cooking may be 

 regarded as the initiatory process of digestion ; 

 for it is not only the softening of raw animal and 



