ction, 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.

(5) Monsters through fusion of parts--one central eye, one nasal
opening, etc.

(6) Monsters through abnormal position or form of parts--curved spine,
face, limb, etc.

(7) Monsters through excess of formation--enormous head, supernumerary
digits, etc.

(8) Monsters through imperfect differentiation of sexual
organs--hermaphrodites.

(9) Double monsters--double-headed, double-bodied, extra limbs, etc.

_Causes._--The causes of monstrosities appear to be very varied. Some
monst