ALTHOUGH the nuiiiber of transplaiitable turnours of the mouse and rat which are now available for the experimental study of malignant new growths is considerable, tumours from the larger laboratory animals, the rabbit and the guinea-pig, in spite of the continuous endeavours of many workers, are still rare. W. H. Schultze (1913 l) described a lynipho-sarcoma of the rabbit which he had transplanted successfully ; and two sarcomata, one from the rabbit and the other from the guinea-pig, have

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... propagated in this laboratory. One of our tumours, a fibro-sarcoma of the rabbit, was propagated with great difficulty for several years, and was finally lost in consequence of intercurrent disease at a time when its powers of growth were in a statc of extreme depression. The other transplantable sarcoma arose in the guinea-pig, and foriiis the subject of the following preliminary note. The animal, an adult female cavy, was found ainong the normal stock of the Lister Institute, and was generously presented to the Imperial Cancer Mesearch Fund by Dr. Ledinghnm. When received, February 27, 1913, the animal was iii good condition and presented a large firm growth ( 2 inches x 3 inches) in the region of the left niainnia. The skin was stretchecl firmly over the tuiiiour, but was not adherent, and the iiipple yrqjected from its surface. After two days the cavy became so serionsly ill that it was considered inadvisalde to attenipl the renioval of the tuniour by operation. The aninial was therefore killed on 3rd March 1913, and at the necropsy portions of the turnour were removed aseptically for transplantation. The lungs showed early consolidation and there was extensive enteritis, otherwise the internal organs appeared free froui pathological changes. There were no macroscopic secondary deposits in the lungs or lymphatic glands. The priniary growth presented an extensive central neciosis, in places almost reaching the delicate hut distiiictly mar1;ed capsule. Rcceired Deceniber 6, 1916.