104 DIGESTION. LECT. V. 



taking place chiefly in the stomach. Thus, then, nothing 

 is more physical than this part of digestion. 



The mastication of aliments impregnated with a slightly- 

 alkaline and warm liquid, is an entirely physical operation 

 similar to that which we practise in our laboratories in order 

 to effect the division of a body, and thereby to promote its 

 solution. 



The gastric juice which the stomach secretes, especially 

 at the moment of digestion, is an infusion of pepsine in 

 acidulated water ; and if we cause it to act on coagulated 

 albumen, on fibrine or caseine, the solution of these sub- 

 stances can be effected as well in a properly warmed re- 

 ceiver as in the stomach. 



The movement of the walls of the stomach promotes the 

 action of the infusion of pepsine upon the substances to be 

 dissolved, just as all agitation aids the reaction of two dis- 

 solved bodies, or the solution of a solid in a liquid. 



This movement of the walls of the stomach, is also of as- 

 sistance in another way : by incessantly renewing the points 

 of contact between them and the matter which they contain, 

 the absorption of the liquid portion of this substance is ef- 

 fected more readily. The influence which the division of 

 the eight pair of nerves has in disturbing digestion, is 

 ascribable, in part, to the cessation of these movements, 

 which are dependent on the action of the nerves. More- 

 over, their section produces a great disturbance in other 

 functions indispensable to the integrity of the animal 

 economy. 



Amylaceous Substances. I shall now speak of the di- 

 gestion of amylaceous matters, a subject on which we have 

 been much enlightened by the beautiful experiment of San- 

 dras and Bouchardat. This experiment is very easily per- 

 formed. A few drops of pancreatic juice, added to some 

 boiled starch or starch jelly, at the temperature of -j- 35 to 



