DYSTOKIA FROM DISPLACEMENT Otf THE UTERUS

229

no matter how slight, the heavy uterus gradually forces itself
through, and may in time escape altogether from the abdomen
along with other viscera.

It would seem that laceration of the abdominal walls may
occur in other ways than through external traumatic influences
or any appreciable occasional cause, and that in some animals
there is a kind of predisposing relaxation or weakening of the
abdominal muscles, which leads to their being unable to

FIG. 69.—UTERINE HERNIA: MAKE.
A, B, Hernial tumour; C, teat carried down by the tumour,

support the gradually increasing strain thrown upon them
by the heavy uterus and its oftentimes very lively and
energetic inmate. The muscles are stretched and attenuated,
their fibres are separated and some of them rupture, and in
this way is formed a rent which gradually enlarges from the
increasing pressure. Then a tumour appears externally and
towards the lower part of the abdomen, though always a little
to one side—usually the left in the mare, the right in the cow
—and not infrequently in front of the pubis, in the mammary

region.