16 Feeds and Feeding. 



28. Gastric digestion of ruminants. — The stomach of the or 

 and sheep is large and has four apartments, viz. — the rumen, ci 

 paunch, the first stomach; the honey comb or reticulum, the second 

 stomach; the m^nyplies or omasum, the third stomach; and the 

 fourth stomach, called the rennet or abomasum. The fourth 

 stomach corresponds to the single stomach of non-ruminants, — 

 the horse, pig, etc. After mastication the food passes from the 

 mouth into the paunch, or first stomach. The first three stomachs 

 secrete no fluid. In the rumen the food becomes very soft and 

 moist, owing to the large amount of saliva secreted and because 

 most of the water drank passes into it. The action of the saliva 

 in converting starch into sugar continues, and a very considerable 

 amount of cellulose may be digested through fermentations, 

 which are favored by the high temperature and the moisture of 

 the contents. The main purpose of the i-umen is to serve as a 

 storehouse for food. The second stomach, or reticulum, which 

 is really a chamber or part of the paunch, contains much fluid, 

 and serves to force the food into the oesophagus for rumination. 

 The food, being returned to the mouth, is reduced to greater fine- 

 ness by chewing, after which it is again swallowed. The second 

 time it passes either to the rumen or the third stomach. It is 

 probable that on being re-swallowed most of the food again drops 

 back into the paunch, and from here the finer portions are forced 

 directly into the third stomach. Like the first and second, the 

 third stomach gives off no secretions, and whatever changes 

 occur in it must be due to the action of the saliva or to fermen- 

 tations begun in the two preceding stomachs. The action of the- 

 first three stomachs on food is preparatory, for the most part, to 

 what occurs in the fourth. The food having been thoroughly 

 prepared by re-chewing and by maceration in the first three 

 stomachs, digestion goes on rapidly in the fourth. Here, as in 

 the stomach of the horse, the albuminoids are changed to pep- 

 tones. Tissues are dissolved and their oil contents set free. Cane 

 sugar is to some extent converted into invert sugar by the action 

 of acid. Starch which escapes conversion into sugar in the 

 rumen passes on into the intestines. Owing to the very thorough 

 preparation of the food in the first three stomachs, gastric diges- 



