With respect to the effect of the operation upon the character and disposition of the cow, these are easily illustrated in the movements of the nymphomaniac animal, which may be said to be constantly in a state of hysterical excitement. They seem to be in continual conditions of heat, running after and mounting other animals with which they may be in company, while never producing and giving no milk. They are always in a lean condition, and must remain a pecuniary loss to the dairyman. This manifestation of nymphomania is also met with in the mare, which, continually exhibiting signs of heat, becomes more or less dangerous on that account. In these cases the advantage of the operation of spaying cannot be overlooked. We have personal knowledge of several cases of this character, in which worthless and troublesome mares have been transformed into docile and valuable animals. CONDITIONS FAVORABLE TO THE OPERATION. Charlier expresses the opinion that the best time for the performance of the operation upon cows is from the sixth to the eighth year, or after they have had their second or third calf. If performed at an earlier period the great objection originally urged against castration, that its performance would tend to the diminution of the stock in numbers or “population,” might find more or less confirmation. But by an observance of this condition all danger of the annihilation of stock would be obviated. The cow to be operated on ought to be in fair condition, not in heat or pregnant, and the time selected should be from forty to sixty days after calving. ANATOMY.