and to hang somewhat downwards. The rectum and skin around it were unaffected. From the vulva a thin yellowish fluid dripped continuously. The anterior part of the pelvic girdle was removed after death, when it was found on slitting up the vagina that the growth affected the whole of its length as well as the external surface of the os uteri, but there was no ulceration through the muscular wall of the vagina. The cavity of the uterus was quite unaffected, as were the bladder and ovary; in fact, there were nowhere any enlarged glands or metastases to the viscera.

Dog B was an extremely emaciated brown bitch. Growth protruded from the vulva as in bitch A, but was larger and was distinctly opaque. Around the vulva and spreading towards the rectum there were scattered patches of ulceration, quite unconnected with the main mass of the tumour, often with bridges of undamaged darkly pigmented skin between them. There were no adhesions to other organs nor was there any invasion of the rectum, though the wall of the vagina was greatly thickened. On slitting up the uterus, the lower part of the unpaired portion was found to be full of bloody slime, and here a separate mass of growth about the size of a split haricot was seen. There were enlarged glands on each side of the belly beneath the superficial fascia, between the groin and the mid-line of the body. There were no metastases in the lungs, liver, pancreas, spleen, or kidneys, but the latter contained a number of minute subcapsular cysts, penetrating certainly not more than from 1 to 2 millimetres into the cortex. The capsules stripped easily. Near both kidneys were certain whitish masses, apparently enlarged glands. They were irregular in shape, and those on the right side lay almost in contact with the vena cava.

Dog C was a thin emaciated male; the prepuce was much swollen, but there was no obvious ulceration. It was found impossible to press the penis out of the prepuce. On slitting up the prepuce, practically the whole of the surface of the penis was seen to be covered with ulcerated growth (fig. 6). The scrotum was swollen to about the size of a man's fist. The testes appeared to be enlarged and to occupy the whole of the pouch, the surface of which was shiny from distention. The scrotum was not invaded, but both testes were absolutely replaced by tumour-tissue resembling that on the inner surface of the prepuce. The tunica albuginea was thin and distended but nowhere ruptured, and there were no adhesions between its two layers. The whole of the inner surface of the prepuce was occupied by papillary growth, ulcerated

in places. There were enlarged glands in both groins. There were no signs of metastasis to the abdominal or thoracic viscera.

Dog D. This was a large reddish-brown well nourished adult male, more stoutly built than the pure bred native dog generally is, and was doubtless of mixed blood.

The prepuce was swollen and much distended, its skin having a shiny appearance. From its orifice there dropped continually a thin, slightly opaque yellowish fluid. On slitting open the prepuce, the whole of the interior surface was seen to be covered with coarsely papillary masses of whitish growth (fig. 7).

The penis itself was for the most part unaffected; but near the reflection of the prepuce on its ventral surface there was a papillary growth occupying an area bigger than a shilling, while proximately to this, on the penis in the neighbourhood of the preputial reflection were many separate small elevations, each about the size of a pin's head (fig. 7). There were no enlarged glands in the groin, abdomen, or pelvis, nor were there any signs of metastasis to the liver, spleen. kidneys, intestines, or lungs.

It is noteworthy that in no case did metastasis to organs beyond the genital system occur, while the enlarged glands which were present in two cases showed no secondary growth but only inflammatory swelling. On the other hand, in animals B and D there was discrete growth at some little distance from the main tumour. In every case the masses when cut into were white and soft, suggesting a round-celled

sarcoma.

The examination of microscopical sections left no doubt in the mind of the writer that the tumours were histologically round-celled sarcomata. In all of them the mass consists of more or less spheroidal cells of uniform size and character. The amount of connective tissue varies, but is in none of the tumours large, and there is no transformation of the tumour cells to fibroblasts. The capillaries are few and small.

I am indebted to Mr. Shattock-who agrees with me that the tumours are histologically indistinguishable from sarcomata-for the following detailed note of the structure in three of the specimens :

Dog C. Testis.-"A dense growth of polyhedral cells, in close apposition, and of uniform character. None show any transformation to fibroblasts. Simple capillaries run among the cells, and here and there a thin stream of connective tissue.

"There is a complete absence of polymorphonuclear leucocytes, of

FIG. 7.-Penis of dog showing a single large lobulated mass and many smaller masses of growth referred to in text, page 38.

UNIV

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