LENGTH OF INTESTINES. 5 



thrown off is almost incredible. But this appears less wonder- 

 ful when the great extent of the lining mucous membrane, 

 from which secretion takes place, owing to the enormous 

 length of the intestinal tube, is taken into account. The 

 resemblance of the hollow trunk of a living animal to a per- 

 forated pillar, though striking, is but distant, as before said ; 

 for the canal which constitutes the hollow of the trunk is very 

 far from being straight. It is so convoluted as to permit of its 

 being of exceeding length. In all mammals that is, in all the 

 order of animals to which common quadrupeds belong the 

 intestines are of considerable extent. In carnivorous quadru- 

 peds they are not so long proportionately as in herbivorous 

 quadrupeds. In omnivorous animals of the mammal class the 

 length is intermediate. In man, as an omnivorous animal, the 

 intestines are six or seven times longer than the body. In the 

 pig, an omnivorous animal, the intestines are thirteen times 

 longer than the body. In the dog, as belonging to the car- 

 nivorous tribe, the intestines are of moderate length : thus, in 

 the mastiff the intestines are about five times the length of 

 the body that is, five times the distance from the muzzle to 

 the root of the tail. The intestines are proportionately longest 

 in ruminant animals, as the sheep and ox. In the sheep the 

 intestines are twenty-eight times longer than the body ; in the 

 ox, twenty-two times longer. In the horse and the animals 

 allied to the horse, as the ass and the zebra, the intestines are 

 shorter than in other vegetable-feeding quadrupeds, and even of 

 less proportionate length than that observed in some omnivo- 

 rous animals. The intestines of the horse, being only ten times 

 longer than the body, do not come up to the standard of the 

 pig, an omnivorous animal, in which, as stated above, the pro- 

 portion is as one to thirteen. In the wild boar, however, the 

 intestines are no more than nine times longer than the body. 

 The quantity of secretion that is, of humid material de- 



