WHY cow's MILK ? 67 



year of illnesses caused by diseases of the digestive 

 tract ? 



Let us examine a little more closely the digestive 

 tract in a cow, a horse, and a man, and note briefly 

 some of the most important features in the digestive 

 process in each case. In the cow we have four stom- 

 achs, each connected with the others, and occupying 

 altogether 70 per cent of the digestive tract. The 

 fourth stomach has its outlet into the intestine, and 

 careful examination will show that the outlet is so 

 small that only liquid, or semi-liquid, food can pass 

 through it. If we could watch the working of this 

 complicated apparatus in the case of a young calf, 

 we should find that the process of digestion goes on 

 about as follows : when the milk of the mother goes 

 into the first stomach it clots with a firm, hard curd. 

 As this clotted mass passes from stomach to stomach, 

 the curd is gradually reduced, until, from the fourth 

 stomach, it passes into the intestine in a digested, 

 liquid form. 



Taking next in order the horse, we find at the outset 

 a very different apparatus. Here is a single stomach, 

 very small, and occupying only about nine per cent 

 of the digestive tract. The outlet from the stomach 

 to the intestine, instead of being so small that only 

 liquid or semi-liquid food can pass through it, is very 

 large. If we could watch the stomach at work during 

 the time the horse was taking a meal, we should find 



