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752 and different forms of new growth, the capacity of the organ may be much diminished. Its mucous surface is generally coated with a sanguineous mucus containing myriads of ova. Gravel, or small stones —generally phosphatic— are sometimes found either embedded in lacunae in the hypertrophied and roughened bladder wall, or free in the cavity. Not infrequently a similar hyperplasia occurs in the ureters, and particularly towards their lower ends. In rare instances the pelvis of the kidney itself is affected. Obliteration of the ureter, both from small stones and from thickening of the mucous membrane, has sometimes been met with; this leads to dilatation of the pelvis and atrophy of the parenchyma of the kidney. It is easy to understand how, in time, these changes in the bladder and ureters may give rise to hydronephrosis, pyelitis, abscess of the kidney, and similar secondary affections.

Hyperplasia from schistosomum infection may also occur in the vesiculae seminales, in the walls of the vagina, and in the cervix of the uterus, leading to corresponding bloody, ova-containing discharges.

When the intestinal tract is involved, numerous polypoid adenomatous growths are found, especially in the rectum; these usually slough off, leaving ulcerations with ragged edges. The coats of the gut become thickened and indurated owing to extensive fibrous tissue formation between the layers of the peritoneal attachments.

It may be mentioned that schistosome ova in small numbers have been found in the liver, in gall-stones, in the lungs, in the heart, and in the kidneys. We have no knowledge of any definite pathological change entailed by their presence there.

Tumours of schistosomum origin have sometimes been found in connection with the peritoneum and ligaments of the uterus.

Diagnosis.— The diagnosis of this disease is not difficult; the presence of ova in the urine is decisive. In countries like Egypt, where the disease must often concur with chyluria, with stone, with vesical tumour, with gonorrhœal cystitis, and with pyelitis, as well as