Causative Agent of a Spontaneously Originating Visceral Tumour in the Newt, Triturus

Abstract

A SPONTANEOUS visceral tumour was found about ten years ago by one of us in the Japanese newt, Triturus pyrrhogaster¹. The original animal showed a number of tumorous nodules in the liver and spleen ranging in size from tiny ones to the largest measuring 1.1 cm × 0.7 cm × 0.4 cm. The tumour was transplanted through many generations to other pyrrhogaster; and it was classified as a lymphosarcoma on the basis of its histogenesis after transmission². It may be transmitted not only to pyrrhogaster but also to other species of newts and salamanders³ and, as we have found recently, to the adult anuran, Xenopus laevis (unpublished). Moreover, the supernatant of tumour homogenates retained the capacity to produce tumour even after the homogenates were frozen and thawed and dried in vacuo. Evidence presented here points to a bacterium as the likely agent.