It may properly be said that there are no complications likely to follow the process in the castration of cows, which may be denominated serious. In the statistics which record the mortality attending it, the fatal cases are represented at the very trifling rate of two per cent. A light colic may sometimes follow it, but it usually subsides without medical treatment. Still, however, spaying may at times be accompanied by accidents of a serious character, though these have considerably diminished in frequency since the introduction of the method of Charlier. One of these is HEMORRHAGE, which may occur when the torsion or the crushing of the artery has not been sufficiently complete. But though it is likely to give rise to peritonitis, it is not necessarily a fatal complication. We have ourselves known of cases of its occurrence in mares which had survived it a number of days, and when destroyed exhibited none of the lesions of that affection. PERITONITIS. We have several times met with this sequel to the operation, especially in mares. But in these cases, as revealed by _post mortem_ investigation, the disease seemed generally to have remained localized. Less common than prior to the practice of castration per vagina, it still is followed by fatal consequences when the entire peritoneum becomes diseased. Its appearance usually occurs from the third to the sixth day. There is suspension of the milky secretion, general dullness, chills, anorexia, suspension of rumination, rapid, small and thready pulse, sometimes painful respiration, rapid loss of flesh, and speedily--death. The indications of treatment are similar to those which are applicable to peritonitis in the solipeds, but the prognosis is always serious. ABSCESS IN THE PELVIC CAVITY. This is a complication we have quite often encountered. Besides the general symptoms, there are those of a local character, which are detected by rectal examination, by which discovery is made of the presence of a tumor on one side or the other of the vagina, varying in size, fluctuating, and easily identified. This abscess may be opened in the cavity of the vagina, and should be attended to as soon as discovery is made of the fluctuating character of the growth, without waiting for the process of natural resolution. SUBCUTANEOUS EMPHYSEMA. Emphysema of the subcutaneous connective tissue is said to be a common sequel to the flank operation. Its appearance need not excite any special uneasiness, as its termination is usually by spontaneous disappearance. It is an accident we have never encountered in our practice. CONSTIPATION. This complication, which is often met with in mares, is to be carefully looked for, and must be relieved by laxative food and rectal injections. It is due to the pain which accompanies defecation while the wound of the vagina is healing, and which the animal tries to avoid by keeping the rectum full. CASTRATION OF THE SMALL ANIMALS. SMALL RUMINANTS.