The method of procedure, which has in his hands proved so exceptionally successful, though no doubt essentially original with him, is still, we believe, based upon the same principles which govern the operation as we find it described and illustrated in the works of the classical writers who have given their attention to the subject. We now turn to the consideration of the _modus operandi_, as observed in the two forms of cryptorchidy, the inguinal and the abdominal. INGUINAL CRYPTORCHIDY. The preliminary steps in this case are the same as those which are necessary in the castration of animals under normal conditions. The instruments required are a convex bistoury, one or two clamps, or a ligature, and an actual cautery, or the ecraseur most commonly in use. To these is sometimes added a pair of long forceps of peculiar construction, with jaws terminating in two spoon-shaped extremities, designed to grasp the testicle when placed high in the inguinal canal, or if only partly engaged in the ring. Prof. Degives divides the operation into five steps. _First; the incision of the scrotum and the dartos._--The operator, with or without the aid of an assistant, makes a straight longitudinal incision upon the scrotum at the place where the testicle is nominally situated, carefully dividing, also, the yellow fibrous layer which represents the dartos, being especially careful at this point to avoid the large venous branches which abound in the region involved. A sort of hooked bistoury is, we understand, preferred by some veterinarians for this incision, on the score of the additional safety secured by the use of an instrument of that form. _Second step; exposure of the external inguinal ring._--To accomplish this the loose cellular tissue which lies under the dartos is torn and divided by the fingers until the ring is felt. The _Third step is the dissection of the vaginal sheath._--The sheath being situated at varying depths, the dissection is effected by carefully introducing the hand into the inguinal canal, and separating it as much as possible by passing the fingers around its external surface. _Fourth step; opening the sheath._--The opening is made lengthwise, and of sufficient width to allow of the passage of the testicle. When this organ is situated high up in the ring, it is frequently difficult to grasp it and keep it sufficiently steady in position to permit the free use of the bistoury. The sheath being opened and all the testicular envelopes divided, we complete the operation by perfecting the