The Gelatinous Mass in Rabbit Semen

Abstract

RABBIT semen consists of two main parts, gelatinous and fluid. After ejaculation, the gelatinous part fills the lumen of the vagina as a copulation plug {bouchon vaginal). The existence of a copulation plug, which prevents the semen running out of the vagina after ejaculation, has been observed¹ in a number of mammals besides rodents. Its importance in rats for fertile mating has been shown by Blandu². That the production and maintenance of the gelatinous mass which mainly constitutes the copulation plug in the rabbit depends on testosterone has been shown by Parsons³. She found that castration in rabbits leads to complete absence of the gelatinous mass in ejaculates. When testosterone propionate was injected into such castrated rabbits, the gelatinous mass reappeared. She further found that implantation of stilbœstrol tablets into a buck previously castrated and implanted with testosterone brought about an inhibition of sex drive as well as a sharp decrease in seminal fructose, but an increase in the gelatinous part. This increase in the gelatinous part, however, remained unexplained.