EMPHYSEMA, OR SWELLING OF THE FETUS WITH GAS.--This has been described as occurring in a living fetus, but I have met with it only in the dead and decomposing foal after futile efforts had been made for several days to effect delivery. These cases are very difficult, as the foal is inflated to such extent that it is impossible to advance it into the passages, and the skin of the fetus and the walls of the womb and vagina have become so dry that it is impracticable to cause the one to glide on the other. The hair comes off any part that may be seized, and the case is rendered the more offensive and dangerous by the very fetid liquids and gases. The only resort is embryotomy, by which I have succeeded in saving a valuable mare that had carried a colt in this condition for four days. CONTRACTIONS OF MUSCLES.--The foal is not always developed symmetrically, but certain groups of muscles are liable to remain short, or to shorten because of persistent spasmodic contraction, so that even the bones become distorted and twisted. This is most common in the neck. The bones of this part and even of the face are drawn to one side and shortened, the head being held firmly to the flank and the jaws being twisted to the right or left. In other cases the flexor muscles of the fore limbs are contracted so that the latter are strongly bent at the knee. In neither of these cases can the distorted part be extended and straightened, so that body or limbs must necessarily present double, and natural delivery is rendered impossible. The bent neck may sometimes be straightened after the muscles have been cut on the side to which it is turned, and the bent limbs after the tendons on the back of the shank bone have been cut across. Failing to accomplish this, the next resort is embryotomy. INCLOSED OVUM, OR TUMORS OF THE FETUS.--Tumors or diseased growths may form on any part of the foal, internal or external, and by their size impede or hinder parturition. In some cases what appears as a tumor is an imprisoned and undeveloped ovum which has grafted itself on the fetus. These are usually sacculated, and may contain skin, hair, muscle, bone, and other natural tissues. The only course to be pursued in such cases is to excise the tumor, or, if this is not feasible, to perform embryotomy. MONSTROSITIES.--Monstrosity in the foal is an occasional cause of difficult parturition, especially such monsters as show excessive development of some part of the body, a displacement or distortion of parts, or a redundancy of parts, as in double monsters. Monsters may be divided into-- (1) Monsters with absence of parts--absence of head, limb, or other organ. (2) Monsters with some part abnormally small--dwarfed head, limb, trunk, etc. (3) Monsters through unnatural division of parts--cleft head, trunk, limbs, etc. (4) Monsters through absence of natural divisions--absence of mouth, nose, eyes, anus, confluent digits, etc.