Six boars were deficient in penile erection and incapable of intromission, but produced ejaculates containing spermatozoa. In five of these boars impotence was primary, but one boar had served normally for two seasons before showing secondary impotence. Sexual libido was good in two, moderate in two and poor in two of these animals. Post mortem studies on the reproductive tracts revealed no abnormalities except in the penes. In one of the boars with primary impotence, the penis showed an abnormal type of spiral deviation during simulated erection, but there was no abnormality in the venous drainage of the organ. In the other five boars, injection experiments revealed venous drainage of the corpus cavernosum penis (ccp) into the dorsolateral (left) tributary of the v dorsalis penis. In four cases, the apical cavernous spaces of the ccp communicated with the vascular spaces of the corpus spongiosum glandis. No direct communications with the corpus spongiosum penis (csp) were demonstrated but the csp was injected from the ccp indirectly, by way of the dorsal venous system. It is suggested that these abnormalities may have been the immediate cause of impotence in these five boars. This possibility is discussed in relationship to the processes of erection and ejaculation and to various clinical signs shown by these animals. The abnormalities of venous drainage were thought to be developmental in origin and the condition may be inherited.

Twenty penis from normal boars were injected with various media at known reservoir pressures and examined by radiography, dissection, maceration, clearing and sectioning. Injections into the corpus spongiosum penis (csp) produced dorsal deviation and clockwise spiral twisting. The ccp was traversed by a system of large longitudinal cavernous spaces. The csp consisted of one large vascular space, its walls joined by trabeculae which were close together ventrally and further apart dorsally. The corpus spongiosum glandis (csg) was a vascular network within the penile integument communicating with the csp by fine vascular spaces around the urethral orifice. The penile arteries and veins were supplied and drained by the internal pudendal vessels. The ccp was drained from its crura by the v profunda penis but no venous drainage of this cavernous body was demonstrated within the body of the penis. The csp was drained from its bulb by the v bulbi penis; its distal extremity was drained by two large veins which ran proximally enclosed by the tunica albuginea of the csp. The right vein was always much larger than the left vein and at the sigmoid flexure the two united to form the right tributary of the v dorsalis penis. The csg and the entire penile integument were drained by the left tributary of the v dorsalis penis; the csg was also drained by one or both of the ventral veins of the csp. Blood from the scrotum was drained by the v circumflexa perinealis and v perinealis ventralis into the v dorsalis penis and v penis. A large dorsal lymphatic vessel drained lymph from the body of the penis into the pelvic lymph nodes. No connections with the superficial inguinal lyphocentres were identified.