In man, this secretion is very weak, comparatively speaking, and hence of small value in preventing such putrefactive changes as those mentioned above. Take any piece of meat, and expose it for some considerable period to an environment of heat and moisture, and see the result! Putrefaction soon occurs—except where the meat is “embalmed” or preserved by powerful chemicals—thus rendering it unfit for human food. But it will be seen that just such conditions prevail in the human alimentary tract as are most suitable for the speedy and deadly decomposition of the food eaten; and, in the case of flesh-foods, the resulting products are poisonous in the last degree. The gastric juice of the human stomach being so far weaker than that of the carnivorous animal, the flesh is far less completely acted upon and digested in the stomach—much more work being passed on to the intestines, in consequence. Now comes in a most important factor. The bowel of the carnivorous animal is, as we have seen, _short_, (three times the length of the body) when compared to the frugivora, whose alimentary tract is about twelve times the length of the body. That is, the digestive tract in man is, roughly, about four times as long as in the carnivorous animal. The result of this is that any food eaten would take, _ceteris paribus_, four times as long to pass through the tube in the one case as in the other. This fact alone is sufficient to condemn the use of flesh-foods in any form for frugivorous animals, since the less active antiseptic and germicidal properties of the gastric juice in these animals render unsafe the long retention of such easily decomposable substances as flesh. But more than that, and worse still; the character of the internal structure of the tract is not alike in the two cases! In the carnivora, this is smooth, and offers but few impediments to the free passage of the food through it. In man, on the contrary, as with the higher apes and the herbivora, the intestine is corrugated or sacculated—this being for the express purpose of retaining the food as long as possible in the intestine, and until all possible nutriment has been abstracted from it. This is admirably suited to such foods as the herbivora and frugivora enjoy, but is quite _un_suited for flesh-foods of all kinds—being, in fact, the worst possible receptacle for such foods. The intestine, in the carnivora, is suited for its particular food—it is short and smooth, and well adapted to dissolve the food quickly and pass it out of the system as rapidly as possible; while in frugivora, on the other hand, the intestine is adapted to retain the food a much longer time—the sacculated surface retaining the food as long as possible. The result of this is that, when flesh-foods are eaten, disastrous results are sure to follow.