PHYSIOLOGY. 183 



Animal matters, treated by calcination, leave ashes in which 

 no alkali is to be found, and the earth is not calcareous nor con- 

 vertible into a quick-lime by any means yet known. 



CCXV. These differences are sufficiently marked ; but it is 

 proper to observe here, that the vegetable matter we treat of, 

 by undergoing a putrefactive fermentation, is changed so as to 

 acquire very exactly most of the characters of animal matter we 

 have just now mentioned. 



CCXVI. The aliment being thus considered, we proceed to 

 consider the changes it undergoes after being taken into the 

 animal body ; but, first, of the course it passes through, and of 

 the motions it is subjected to in its progress. 



CCXVII. The aliment is taken into the mouth, and there 

 the more solid parts of it are commonly subjected to a triture, 

 or what is called manducation. At the same tune a quantity 

 of saliva, and of the other fluids of the mouth, with some por- 

 tion of our drink, is intimately mixed with it, whereby the 

 whole is reduced to a soft pulpy mass. In this state, by the 

 action of deglutition, it passes through the fauces into the oeso- 

 phagus, by which it is conveyed into the stomach. 



CCXVI II. Here the aliment is detained for some time, 

 subjected to a constant agitation and some pressure, both by 

 the contractions of the different parts of the stomach itself, and 

 by the alternate pressure of the diaphragm and abdominal mus- 

 cles. After some time, however, first the more fluid parts, and 

 at length the most minute parts of the solid matter are pushed 

 through the pylorus into the duodenum. 



CCXIX. The matters received from the stomach into the 

 duodenum pass on from thence successively through the several 

 parts of the intestinal canal; and, in the whole of the course, 

 the matters are still subjected to the alternate pressure of the 

 diaphragm and abdominal muscles, and to the contractions of 

 the intestines themselves. 



CCXX. Through the whole course of the intestines, but 

 especially the small, the more fluid part of the contents, and 

 particularly the peculiar fluid we name chyle, is taken into the 

 vessels named lacteals. These, from imperceptible beginnings 

 on the internal surface of the intestines, unite into larger vessels 

 laid in the mesentery, and convey the chyle, and what accom- 



