156 - ANALYTIC SECT. XIX. 
SECTION. XIX, 
Digestion. 
cccLxxxvi. By digestion, is understood the 
transmutation of substances in the alimentary 
canal, and their separation into chyle and feces. 
The diversity of thinking, and the discrepaney of 
facts which prevail on this important part of phy- 
siology, invite to further inquiry and experiment, 
to extricate it from the doubt and obscurity in 
which it is involved. 
cccLxxxvi1. Hippocrates, and the ancients in 
general, considered digestion a sort of coction or 
boiling of the food; heat, according to this doc- 
trine, is the primary agent of alimentary decom- 
position, and without it, Aristotle asserts that no 
solution can be effected: the sentence in which 
this idea is expressed is worthy of quotation, from 
the sound physiological notions which it conveys: 
* Non enim concoctio, sine anima et calore absolvi 
potest.” 
CCCLxxxvull. Pringle and Macbride contended, _ 
that digestion is an operation of the particles of — 
