_Preventive._--The true preventive of such conditions is to be found in a sound hygiene. The breeding animal should be of adult age, neither overfed nor underfed, but well fed and moderately exercised; in other words, the most vigorous health should be sought, not only that a strong race may be propagated, but that the whole herd, or nearly so, may breed with certainty. Fleming gives 79 per cent as the general average of cows that are found to breed in one year. Here more than a fifth of the progeny is sacrificed and a fifth of the product of the dairy. With careful management the proportion of breeders should approach 100 per cent. The various local and general obstacles to conception should be carefully investigated and removed. The vigorous health which comes from a sufficiently liberal diet and abundant exercise should be solicited, and the comparative bloodlessness and weakness which advance with undue fattening should be sedulously avoided. In bull or cow which is becoming unduly fat and showing indications of sexual indifference, the treatment must be active. Turning out on a short pasture where it must work hard for a living will often suffice. The bull which can not be turned out to pasture may sometimes be utilized in the yoke or tread power, or he may be kept a part of his time in a field or paddock chained by the ring in his nose to a strong wire extending from one side of the lot to the other and attached securely to two trees or posts. The wire should be higher than the back of the bull, which will move frequently from end to end. If he is indisposed to take sufficient exercise in this way he may be safely driven. An instance of the value of the exercise in these incipient cases of fatty degeneration is often quoted. The cow Dodona, condemned as barren at Earl Spencer's, was sold cheap to Jonas Webb, who had her driven by a road a distance of 120 miles to his farm at Wilbraham, soon after which she became pregnant. In advanced cases, however, in which the fatty degeneration is complete, recovery is impossible. In case of rigid closure of the mouth of the womb the only resort is dilatation. This is far more difficult and uncertain in the cow than in the mare. The neck of the womb is longer, is often tortuous in its course, and its walls so approximated to each other and so rigid that it may be all but impossible to follow it, and there is always danger of perforating its walls and opening into the cavity of the abdomen, or, short of that, of causing inflammation and a new, rigid, fibrous formation which on healing leaves matters worse than before. The opening must be carefully made with the finger, and when that has entered the womb further dilatation may be effected by inserting a sponge tent or by careful stretching with a mechanical dilator. (Pl. XX, fig. 6.) STERILITY FROM OTHER CAUSES.