4. The capria of the sow is also cut out, so that they should not desire coition, but fatten rapidly. They are cut after fasting two days. They hang them up by the hind legs and make an incision in the lower part of the belly, where the testicles of the male are generally found; the capria is there formed upon the matrix, from which they cut off a portion, and sew up the wound again. 5. The female camels also are cut when they wish to take them to war, that they may not become pregnant. Some of those in the upper parts of Asia possess as many as three thousand. Such camels, when they run, are far more swift than the Nisæan horses, from the length of their stretch. And on the whole, castrated animals are longer-bodied than those not castrated. 6. All animals that ruminate, derive as much use and pleasure from rumination as from eating. Animals that have not cutting-teeth in both jaws ruminate, as the ox, sheep, and goat. No observations have been made on wild animals except those which occasionally associate with men, as the stag, though this animal ruminates. They all lie down to ruminate, and do so most in the winter; those which are brought up in shelter ruminate for nearly seven months. Those that live in herds, ruminate for a shorter period, for they live out of doors. Some animals with cutting teeth in both jaws, ruminate, as the Pontic mice and the fish, which, from this process, is called meryx. Animals with long legs have loose bellies, and those with broad chests vomit more easily than others, in quadrupeds, birds, and the generality of mankind. BOOK THE TENTH. (ERRONEOUSLY ASCRIBED TO ARISTOTLE.) CHAPTER I. If men and women, after they have reached a certain age, do not have children after cohabitation, the fault sometimes rests with both, and sometimes in only one of them. And first, it is requisite to examine the uterus of the female, that if the fault lies there it may be relieved by proper treatment. If the fault is not there, attention must be paid to some other cause of sterility. We may conclude that this organ is in a healthy state, when, like the other parts of the body, it performs its functions without pain, and is free from fatigue after the function is performed. Just as the eye is in a healthy state if it suffers no pain in seeing, and is not disordered with the exercise of its function, or unable to perform it again, so the uterus is healthy which suffers no pain, and is well able to perform its functions, whatever they may be, and after they are performed is not impotent, but is free from fatigue.