vin] in the Eighteenth Century. 221 



"the substance possessed of it from dissolution, and from being 

 " changed according to the natural changes which other sub- 

 " stances undergo." The doctrine here laid down is, it will be 

 observed, almost identical with that of Stahl. 



In his first paper Hunter states that " the appearances of 

 " the stomach found to be digested after death shew that 

 " digestion neither depends on a mechanical power, nor contrac- 

 " tions of the stomach, nor on heat, but on something secreted 

 " in the coats of the stomach, and thrown into its cavity, which 

 " there animalizes the food or assimilates it to the nature, of 

 " blood." The instances of the stomach digesting itself interested 

 him, because he maintained that "animals or parts of animals, 

 " possessed of the living principle, when taken into the stomach, 

 " are not in the least affected by the powers of that viscus, so 

 " long as the animal principle remains." And he explained the 

 auto-digestion as due to the walls of the stomach ceasing to be 

 alive and becoming subject to the power still remaining in the 

 gastric juice which they had themselves secreted. 



Hunter is very clear that digestion is not fermentation. 

 He speaks of the vinous and acetous fermentation to which 

 vegetable substances are prone and of the putrefactive fermenta- 

 tion to which animal substances are subject. And he argues 

 as follows: — "It may be admitted as an axiom that two processes 

 "cannot go on at the same time in the same part of any 

 " substance ; therefore neither vegetable nor animal substances 

 " can undergo their spontaneous changes while in the act of 

 "being digested, it being a process superior in power to that of 

 "fermentation. * * * The gastric juice therefore preserves 

 " vegetables from running into fermentation and animal sub- 

 " stances from putrefaction ; not from any antiseptic quality in 

 " the juice, but, by making them go through another process, 

 " preventing the spontaneous change from taking place." 



And he developes his view more fully as follows : " The 

 " process of digestion differs from every other natural operation 

 "in the change it produces on different bodies; yet it is by no 

 " means fermentation, though it may resemble it. For fer- 

 " mentation, a spontaneous process, is that natural succession 

 "of changes by which vegetable and animal matter is reduced 



