Castration and Transplantation

The conspicuous phenomena observed in humans and animals after castration had long suggested that the reproductive glands had an important influence on the organism’s structure and function. It was therefore no coincidence that Brown-Séquard’s organotherapy started with the testicles. By administering testicular extract to improve physical strength and intellectual alertness, the scientist based his treatments on ideas generally accepted at the time about male sex glands. Eunuchs and castrati displayed what were considered mental and physical deficiencies that went beyond sexuality alone, and common opinion held that the loss of sperm caused a debilitation of the entire organism, especially of the nervous system. Based on these assumptions, therapy with extracts and testicle transplants continued to be associated with the hope for eternal youth well into the first half of the twentieth century, and organotherapy with testicle preparations in pill or liquid form to remedy nervous ailments remained very popular for a long time as well. In parallel to these popular ideas about the effects of testicular therapy, doctors and scientists were working on the definition and specification of the organ’s internal secretion, proceeding along the lines of the developing field of endocrinology. At first they only approached the subject very cautiously. In view of the promises of rejuvenation made for testicular extracts, they were afraid of placing themselves on the same unscientific level as quacks and charlatans. Only once the concepts and methods of the scientifically and experimentally founded field of endocrinology were in place, could they explore the internal secretion of the testicles within the scope of scientific medicine.

In their work on the hormone concept, physiologists started examining the influence of the testicles on the organism as a whole. Before hormones were seen as the agents of sex differentiation, the development of external sex characteristics was usually explained as a physiological process regulated by the nervous system. As in the case of other organs, however, ablation and transplantation experiments pointed to the possibility that the process might be controlled instead by an internal secretion emanating from the testicles.