owth along a given natural line is very highly developed in the
early embryo and is equally manifest in the mature examples of some of the
lower forms of animal life. Thus a newt will grow a new tail when that
member has been cut off, and a starfish will develop as many new starfishes
as the pieces made by cutting up the original one. This power of growth in
the embryo and in the lower form of animals is comparable to the branching
out again of a tree at the places from which branches have been lopped. The
presence of this vegetablelike power of growth in the embryo accounts for
most double monsters.

The influence of disease in modifying growth in the early embryo,
increasing, decreasing, distorting, etc., is well illustrated in the
experiments of St. Hilaire and Valentine in varnishing, shaking, or
otherwise disturbing the connections of eggs and thereby producing
monstrosities. One can easily understand how inflammations and other causes
of disturbed circulation in the womb, fetal membranes, or fetus would cause
similar distortions and variations in the growing fetus. It is doubtless
largely in the same way that certain mental disturbances of a very
susceptible dam affect the appearance of the progeny. The monstrosities
which seriously interfere with calving are mainly such as consist in extra
members or head, which can not be admitted into the passages at the same
time, where some organ of the body has attained extra size, where a
blighted ovum has been inclosed in the body of a more perfect one, or where
the body or limbs are so contracted or twisted that the calf must enter the
passages doubled up.

_Treatment._--Extraction is sometimes possible by straightening the
distorted members by the force of traction; in other cases the muscles or
tendons must be cut across on the side to which the body or limbs are bent
to allow of such straightening. Thus, the muscles on the concave side of a
wry neck or the cords behind the shank bones of a contracted limb may be
cut to allow of these parts being brought into the passages, and there will
still be wanting the methods demanded for bringing up missing limbs or
head, for which see paragraphs below. In most cases of monstrosity by
excess of overgrowth it becomes necessary to cut off the supernumerary or
overdeveloped parts, and the same general principles must be followed as
laid down in "Embryotomy" (p. 202).

WRONG PRESENTATIONS OF THE CALF.

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