The cow, of all our domestic animals, is especially subject to this accident. This may be partly accounted for by the firm connections established through the fifty to one hundred cotyledons (Pl. XIII, fig. 2) in which the fetal membranes dovetail with the follicles of the womb. It is also most liable to occur after abortion, in which preparation has not been made by fatty degeneration for the severance of these close connections. In the occurrence of inflammation, causing the formation of new tissue between the membranes and the womb, we find the occasion of unnaturally firm adhesions which prevent the spontaneous detachment of the membranes. Again, in low conditions of health and an imperfect power of contraction we find a potent cause of retention, the general debility showing particularly in the indisposition of the womb to contract, after calving, with sufficient energy to expel the afterbirth. Hence we find the condition common with insufficient or innutritious feed, and in years or localities in which the fodder has suffered from weather. Ergoted, smutty, or musty fodder (Pl. V), by causing abortion, is a frequent cause of retention. Old cows are more subject than young ones, probably because of diminishing vigor. A temporary retention is sometimes owing to a too rapid closure of the neck of the womb after calving, causing strangulation and imprisonment of the membranes. Conditions favoring this are the drinking of cold (iced) water, the eating of cold feed (frosted roots), and (through sympathy between udder and womb) a too prompt sucking by the calf or milking by the attendant. _Symptoms._--The symptoms of retention of the afterbirth are usually only too evident, as the membranes hang from the vulva and rot away gradually, causing the most offensive odor throughout the building. When retained within the womb by closure of its mouth and similarly in cases in which the protruded part has rotted off, the decomposition continues and the fetid products escaping by the vulva appear in offensively smelling pools on the floor and mat together the hairs near the root of the tail. The septic materials retained in the womb cause inflammation of its lining membrane, and this, together with the absorption into the blood of the products of putrefaction, leads to ill health, emaciation, and drying up of the milk.