Douglas McClean

THE INFLUENCE ON TISSUE PERMEABILITY OF A SUBSTANCE EXTRACTED FROM MAMMALIAN TESTES

DURING the past four years many papers have appeared in journals of experimental pathology in which the influence of an aqueous extract of mammalian testes on dermal infections with various viruses and bacteria have been described. The action on lesions produced by toxins and on the growth of tumour transplants have also been investigated. When this extract is added to the infecting agent and the mixture is inoculated intradermally the local lesion is markedly increased in size and altered in macroscopic appearance. The lesion is associated with an increased oedema of the surrounding skin and subcutaneous tissues, and, in some instances, the general invasive power of the infective or toxic agent is enhanced. Some of the workers described and investigated the direct effect of this extract on the dermis-whereby the permeability of this tissue to injected material is greatly increased, and their experiments suggest that this alteration of permeability is responsible for the augmented size of the lesions. The enhanced permeability does not require delicate methods for its appreciation; it is an immediate and striking phenomenon that is easily visible to the naked eye. The ability of testicular extract to increase the permeability of the dermis and other tissues is of considerable biological interest and it is for this reason that it has