SummaryType A secretory cells (Sluiter and Van Oordt) are found in great number wherever secondary sex characteristics are well developed. In patient Th... in whom the latter are slightly deficient, they are less numerous and mostly localized in isolated and definitely hyperplastic islets of interstitial cells. Well developed interstitial cells, with lipoïdic inclusions, are found in eunuchoid patients in whom the secondary sex characteristics are rarely encountered. Moreover they are definitely localized around the best preserved of the tubules; this is in accord with their presumed trophic role.Biopsy of such testicular lesion may he of interest for another reason. Connections between interstitial elements and nervous fibres should have to ho looked for. This study might improve our knowledge on the possible role of the central nerves system on quantitative and quantitative changes of their secrection.