THE ANIMAL BODY— DIGESTION— METABOLISM 21 



expanded just before the true stomach is reached into three compart- 

 ments of great aggregate capacity, the first and by far the largest of 

 which is the paunch; the second, the honeycomb; and the third, the 

 manyplies. The 4 stomachs of a full grown steer may hold over 250 

 quarts, while the single stomach of a horse holds only 12 to 19 quarts, 

 and of a pig about 8.5 quarts. 



The small intestine is the long, folded, tortuous tube into which the 

 stomach empties. It is about 130 ft. long in mature cattle, 70 ft. in 

 horses, 80 ft. in sheep, and 60 ft. in swine. Its average capacity is 

 about as follows : cattle, 70 quarts ; horse, 50 to 65 quarts ; sheep and 

 swine, 10 quarts. The large intestine, into which the small intestine 

 empties, is larger in diameter but much shorter. In the horse, that 

 part of the large intestine next to the small intestine, called the 

 blind gut, or caecum, is greatly enlarged. Due to this, the large 

 intestine of this animal holds from 120 to 140 quarts. Were it not 

 for this caecum, the horse would be unable to consume and digest 

 large amounts of roughage. In cattle the large intestine has a capacity 

 of about 40 quarts, and in sheep 6 quarts. The pig, which has neither 

 the 4 stomachs of the ruminants nor the large caecum of the horse, is 

 not well fitted to use large amounts of roughage. His large intestine, 

 however, holds nearly twice as much as that of the sheep, which aids 

 him somewhat in disposing of coarse feed. 



Mastication. — In the mouth the food is crushed and ground by the 

 teeth and at the same time moistened by the alkaline, somewhat slimj'-, 

 saliva, moist and slippery masses being formed which pass readily 

 thru the gullet into the stomach. Exceedingly large amounts of saliva 

 are secreted by the larger farm animals, especially when eating dry 

 feed. For example, a horse may secrete as much as 90 lbs. during 

 24 hours. 



Ruminants while eating chew their food only enough to moisten it, 

 if dry, and form it into masses of suitable size to be swallowed. The 

 gullet of ruminants opens into the first 3 stomachs thru a slit called 

 the esophageal groove, which has an exceedingly important function. 

 When the ox swallows the masses of solid food, which are so large as 

 to distend the gullet, on coming to the slit they are pressed out thru it, 

 just as would be the case if one tried to force thru a rubber tube with 

 a slit in it an object like a ball which fitted it tightly. These masses 

 of food usually pass into the paunch until it is full, and then on into 

 the honeycomb instead. When hunger is satisfied the animal seeks a 

 quiet place and proceeds to ruminate, or "chew the cud." By con- 

 tractions of the muscular paunch, the honeycomb, and of the gullet 

 itself, the food is forced back to the mouth in "cuds." Here each cud 

 is thoroly chewed and saliva is added until the material becomes more 



