ease, but the true source of the trouble is likely to be detected
only if the heads or hooklets of the tapeworm or the eggs of the roundworm
are found on microscopical examination of the urine.

TUMORS OF THE KIDNEY (HYPERTROPHY OR ATROPHY).

The kidney may be the seat of cancerous or simple tumors, and it may be
unnaturally enlarged or reduced in size, but though there may be signs of
urinary disorder the true nature of the disease is seldom manifest until
after death. The passing of blood and of large multi-nucleated cells in
the urine (to be detected under the microscope) may betray the existence of
an ulcerated cancer of the kidney. The presence of cancerous enlargement of
(superficial) lymphatic glands may further assist and confirm the decision.

RETENTION OF URINE.

Inability to pass urine may come from any one of three conditions--first,
spasm of the neck of the bladder; second, paralysis of the body of the
bladder; third, obstruction of the channel of outlet by a stone (calculus)
(see Pl. XI) or other obstacle.

In _spasm of the neck of the bladder_ the male animal may stand with the
tail slightly raised and making rhythmical contractions of the muscle
beneath the anus (accelerator urinae) (see Pl. IX, fig. 2), but without
passing a drop of liquid. In the female the hind legs are extended, widely
parted, and the back is arched as if to urinate, but the effort is vain. If
the oiled hand is introduced into the rectum or vagina in the early stages
of the affection, the bladder may be felt beneath partially filled, but not
overdistended with liquid, and its neck or mouth firm and rigid. In the
more advanced stages of the affection the organ is felt as a great, tense,
elastic bag, extending forward into the abdomen. In this condition the
overdistended muscular coat of the bladder has lost its power of
contraction, so that true paralysis has set in, the muscle closing the
mouth of the sac alone retaining its contractile power.

In _paralysis of the body of the bladder_ attention is rarely drawn to the
urinary disorder until the bladder has been distended to full repletion and
is almost ready to give way by rupture and to allow the escape of the
contained liquid into the abdomen. Overdistention is the most common cause
of the paralysis, yet it may occur from inflammation of the muscular wall
of the bladder, or even from injury to the terminal part of the spinal
marrow. In this last condition, however, the tail