SUMMARY
Hypophyseal tumours in mice develop after prolonged treatment with oestrogens, after injection of radioactive iodine in doses which destroy the thyroid tissue and after prolonged treatment with thiouracil-derivatives. The tumours of the hypophysis only occur in certain strains of mice and hence the genetic constitution is of importance. The origin of this difference between strains has hitherto remained completely obscure. The hypophyseal tumours in mice seen following administration of oestrogens and those observed after destruction of the thyroid gland are morphologically similar. They consist of cells staining blue to varying degrees, and they may thus be termed amphophile tumours. The possible mechanism of development of the hypophyseal tumours has been discussed.
