118 YBTERINAEY STATE BOARD 



another enzyme, rennin, which curdles milk. In the stomach of 

 dogs, free hydrochloric acid is present; it aids in the digesting 

 of bone. 



Give the composition of gastric juice. From what is the hydrochloric 

 acid derived? 

 Water, hydrochloric acid, lactic acid, pepsin, rennin, chlorides, 

 phosphates and iron. 



The hydrochloric acid of the gastric juice is thought to be 

 derived from the gastric glands which form it from the chlorides, 

 which the mucous membrane takes up from the blood. 



Describe the digestion of proteids in the stomach. 



Pepsin converts proteids into peptones. This change is effected 

 through several stages. The intermediate products in the order in 

 which thej' occur are: 



1. The prbteid as consumed, or native albumin. 



2. Acid albumin, or syntonin. 



3. Primary proteoses. 



4. Secondary proteoses. 



5. Peptones. 



How many stomachs has (a) the horse, (b) the ox, (c) the goat, (d) 

 the camel? 

 (a) One; (b), (c) and (d) one stomach divided into four com- 

 partments, which gives rise to the common statement that they have 

 four stomachs. The fourth compartment, the abomasum, is the 

 time stomach and is practically the same as the stomach of other 

 animals. 



State the condition of food as it leaves the abomasum. 



It is a soft, pasty mass with a sour odor and alkaline reaction; 

 the proteids have been converted into peptones and the starch is 

 said to have been digested. In the young, the milk has been curdled..' 



State the extent of the secreting (peptic) mucosa, as compared with 

 the non-peptic, in the stomach of the horse, hog and dog 

 and in the fourth stomach of the ox. 

 In the horse, the peptic mucosa constitutes about two-thirds of 

 the whole lining of the stomach, the non-peptic the remainder. 



In the hog, the peptic mucosa constitutes about one-third, the 

 remainder being non-peptic. 



In the dog, the peptic mucosa extends over the whole extent of 

 the stomach wall. 



