III - The hydatids of Morgagni under normal and experimental conditions

Anatomical investigations of the appendages attached to the testis and epididymis began with enquiries into the origin of the fluid found in hydrocoeles. Morgagni (1682-1771), who was the first to draw attention to these minute structures, was opposed to the hypothesis that the tunica vaginalis is a secreting membrane. In place of that view, he advocated the opinion (1769) that the fluid is derived from ruptured testicular and epididymal hydatids. The several investigations which followed Morgagni’s observations showed clearly that his designation of these bodies as hydatids is fundamentally incorrect. Partly because of alternative descriptions advanced by subsequent workers, and partly because the subject has not been seriously considered since the earlier years of the present century, textbook descriptions of the testicular and epididymal appendages vary greatly with respect to the number, nomenclature, topography and embryological significance of these bodies. The following synthesis of available views regarding the hydatids in man provides a necessary background to the consideration of the corresponding structures in monkeys, from which the material for the experimental work recorded in this paper was obtained.