According to Ross, writing in 1932, some 131 cases of chorionepithelioma testis had been published up to that time. In a survey of the literature since that date I have encountered records of a further 11 cases in some of which due recognition has been made of the value of the Zondek-Aschheim reaction in assessing the biological equivalence of this tumour and the uterine chorionepithelioma of Marchand, which was first investigated by Heidrich, Fels and Mathias (1930). Storjohann (1932) describes a case occurring in a patient of twenty-eight. Orchidectomy was performed for testicular enlargement of two years standing, accompanied by gynaecomastia. The primary growth showed chorion-epithelioma with insignificant teratomatous components, and the gynaecomastia appeared to recede after operation. Death occurred in two months with pulmonary and cerebral metastases. The pituitary showed a “pregnancy reaction.” Welchman (1933) reports a case in a man of twenty-nine in which a diagnosis of chorionepithelioma testis was made by biopsy of the primary tumour and a secondarily invaded cervical lymph node. Later there was rapid deterioration attended by clinical findings suggestive of metastases in lung, liver, and spine. Deep x-ray therapy associated with preradiation treatment with insulin and glucose was followed by recovery, the patient being alive and well five years later. The rationale of this treatment appears to depend on the author's suggestion that the increased carbohydrate content of the tumour cells (normally lower than that of healthy cells), which might be expected to follow the administration of glucose, so stimulated their growth as to render them radiosensitive.