The pressure of the distended womb on the nerves and blood vessels of the pelvis, besides conducing to dropsy, occasionally causes cramps of the hind limbs. The limb is raised without flexing the joints, the front of the hoof being directed toward the ground, or, the spasms occurring intermittently, the foot is kicked violently against the ground several times in rapid succession. The muscles are felt to be firm and rigid. The cramp may be promptly relieved by active rubbing or by walking the animal about, and it does not reappear after parturition. CONSTIPATION. This may result from compression by gravid womb, and is best corrected by a graduated allowance of boiled flaxseed. PARALYSIS. The pressure on the nerves of the pelvis is liable to cause paralysis of the hind limbs or of the nerve of sight. These are obstinate until after parturition, when they recover spontaneously, or under a course of nux vomica and (local) stimulating liniments. PROLONGED RETENTION OF THE FETUS (FOAL). Though far less frequently than in the case of the cow, parturition may not be completed at term, and the mare, to her serious and even fatal injury, may carry the foal in the womb for a number of months. Hamon records one case in which the mare died after carrying the fetus for 17 months, and Caillier a similar result after it had been carried 22 months. In these cases the fetus retained its natural form, but in one reported by Gohier the bones only were left in the womb amid a mass of apparently purulent matter. _Cause._--The cause may be any effective obstruction to the act of parturition, such as lack of contractile power in the womb, unduly strong (inflammatory) adhesions between the womb and the fetal membranes, wrong presentation of the fetus, contracted pelvis (from fracture or disease of the bones), or disease and induration of the neck of the womb. The mere prolongation of gestation does not necessarily entail the death of the foal; hence the latter has been born alive at the four hundredth day. Even when the foal has perished putrefaction does not set in unless the membranes (water bags) have been ruptured and septic bacteria have been admitted to the interior of the womb. In the latter case a fetid decomposition advances rapidly, and the mare usually perishes from poisoning with the putrid matters absorbed.