denly stop
short in the act. In the first three of these only (a, b, and c)
is there real sterility in the sense of the nondevelopment or imperfect
development of the male vivifying element (spermatozoa). In the other
examples the secretion may be imperfect in kind and amount, but as
copulation is prevented it can not reach and impregnate the ovum.

In the mare barrenness is equally due to a variety of causes. In a
number of breeding studs the proportion of sterile mares has varied from
20 to 40 per cent. It may be due to: (a) Imperfect development of the
ovary and nonmaturation of ova; (b) cystic or other tumors of the
ovary; (c) fatty degeneration of the ovary in very obese, pampered
mares; (d) fatty degeneration of the excretory tubes of the ovaries
(Fallopian tubes); (e) catarrh of the womb, with mucopurulent
discharge; (f) irritable condition of the womb, with profuse
secretion, straining, and ejection of the semen; (g) nervous
irritability, leading to the same expulsion of the male element; (h)
high condition (plethora), with profuse secretion and excitement; (i)
low condition, with imperfect maturation of the ova and lack of sexual
desire; (j) poor feeding, overwork, and chronic debilitating diseases,
as leading to the condition just named; (k) closure of the neck of the
womb, temporarily by spasm or permanently by inflammation and
induration; (l) closure of the entrance to the vagina through
imperforate hymen, a rare, though not unknown, condition in the mare;
(m) acquired indisposition to breed, seen in old, hard-worked mares
which are first put to the stallion when aged; (n) change of climate
has repeatedly been followed by barrenness; (o) hybridity, which in
male and female alike usually entails sterility.

_Treatment._--The treatment of the majority of these conditions will be
found dealt with in other parts of this work, so that it is only
necessary here to name them as causes. Some, however, must be specially
referred to in this place. Stallions with undescended testicles are
beyond the reach of medicine, and should be castrated and devoted to
other uses. Indurated testicles may sometimes be remedied in the early
stages by smearing with a weak iodin ointment daily for a length of
time, and at the same time invigorating the system by liberal feeding
and judicious work. Fatty degeneration is best met by an albuminoid diet
(wheat bran, cottonseed meal, rape cake) and constant, well-regulated
work. Saccharin