104 TEXT-BOOK OF ZOOLOGY 



prolonged, in the shape of a gutter or half-tube, into the third compart- 

 ment. When the edges of this gutter stand apart, the food falls into 

 the paunch ; when, however, they are applied against each other, thus 

 converting the gutter into a perfect tube, the ruminated food is conveyed 

 into the psalterium. Digestion proper does not take place until the food 

 enters the last compartment, the abomasum, or rennet stomach (see p. 8). 

 It takes the latter of its names from a peculiar secretion of its mucous 

 membrane, the rennet, which in the stomach of the young calf causes 

 the milk of the mother to curdle. 



C. The Ox as a Domestic Animal. 



We have seen how rumination implies a saving of force, and con- 

 sequently of food. This capacity is not only of great value to the 

 animal, but also to man. The ox, in fact, in virtue of this ruminating 

 capacity, from a certain amount of food unfit for human consumption 

 (grass, flowers of the field, etc.], produces a larger quantity of food suitable 

 for human nourishment (meat, fat, milk) than it otherwise would, and, if 

 supplied ivith an abundance of fodder, is more rapidly and easily fattened.. 



All mammals produce milk only as a nourishment for their young. 

 When these are capable of finding their own food, the parents refuse 

 them further access to the teat, and the nourishing spring dries up. 

 With his domestic cattle, however (cow, goat, reindeer, camel, and in 

 some parts even horses), man does not allow matters to proceed so far. 

 He assumes to himself the part played by the young, for by constant 

 removal of the milk (milking) he stimulates the milk-glands so that they con- 

 tinue to secrete for a longer period. The cow, having but one or at most 

 two calves at a time, is provided with only four teats (compare, on the 

 contrary, the large number of teats in the pig, dog, cat, etc., in relation 

 to the large number of their young). The value of cow's milk to man 

 (as a source of butter and cheese), and the further uses of this animal 

 by reason of its flesh, fat, hide, hair, horns, and bodily strength, are 

 too well known to need further discussion. 



D. The Nearest Relatives of the Ox. 



The representative of the ox in India and East Africa is the Zebu, 

 or Humped Ox, of which there are several breeds or varieties. It 

 derives its second name from a hump of fat on the front part of the 

 back (see camel). For the performance of labours of various kinds, and 

 for riding, and also on account of its flesh and milk, it is of the highest 

 importance. 



In the Buffaloes (Bubalus) the horns are placed on the skull not far 

 from the eyes, and are very thick at the roots. Among these we must 



