The cytology of tar tumours

Abstract

Numerous experiments carried out within recent years have shown that the regular application of tar to the skin of the mouse induces tumour growth, which may ultimately become malignant. The general microscopic anatomy of tar cancers, produced in the laboratories of the Imperial Cancer Research Fund, have been described by J. A. Murray and W. H. Woglom (14). These investigators have shown that the malignant condition supervenes in small isolated foci, within the area painted with tar, and is not a diffused change, affecting all the cells exposed to irritation. Further, the degree of differentiation of the epidermal cells of the tumour varies considerably. In general, the more easily the carcinomatous condition is produced, the nearer the normal is the differentiation shown by the tumour, and vice versâ. The present research was carried out in order to compare the cytological characters of the cells of normal skin with those of tar tumours, special attention being paid to the Golgi apparatus of the cells. The tar tumours of the mouse described in this paper were produced experimentally in the laboratories of the Imperial Cancer Research Fund, and the material was placed at my disposal by the Director, Dr. J. A. Murray, F. R. S. The technique employed for the study of the various cell organs is summarised below.