316 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



like a honeycomb. The psalter or manyplies (3), as its 

 name indicates, has its mucous membrane thrown into 

 many wide and thin folds, like the leaves of a book. It 

 is probable that the digestion of starch (saccharization) 

 takes place here, and is all the more complete because 

 the acid gastric juice is not secreted until we reach the 

 last compartment. Finally, the abomasum or rennet (4) 

 is the true and final digestive stomach, where pepsin is 

 formed and peptonization takes place. 



We see, then, that several functions which are com- 

 bined in the same organ in most animals are here dif- 

 ferentiated with more perfect results. The reason of 

 this is found in the nature of the food and the habits of 

 the animals. The food consists of grasses and herbage, 

 in which the amount of nutritious matter is so small that 

 they must take a very large quantity, and therefore the 

 stomach must be correspondingly large. But again, on 

 account of the small percentage of nutritious matter, 

 the food must be very thoroughly triturated and the di- 

 gestive process very complete so as to extract it all. 

 We have already seen how well their teeth are adapted 

 to thorough trituration ; we see also how the stomach is 

 adapted to perfect digestion. But perfect trituration of 

 so large an amount of food would take much time, and 

 these animals are timid and preyed upon by carnivores. 

 Therefore they are compelled to take their food rapidly, 

 imperfectly chewing and hastily packing it away in the 

 paunch, where it is soaked and softened. Then at their 

 leisure they lie in some concealed place and ruminate, or 

 chew the cud. Every one must have observed the pro- 

 cess in domestic animals, and perhaps envied their pla- 

 cidity of mind. If we observe closely we see the chew- 

 ing stop a while; the bolus goes down the gullet by 

 peristalsis, then another comes up by antiperistalsis, 

 and the chewing recommences and continues until the 



