iv THE GENERATIVE SYSTEM OF THE MALE 143 



To account for the mechanism of erection, the Ancients 

 imagined that a mechanical obstacle to the circulation of the 

 blood in the organ arose during the venereal orgasm, producing a 

 stasis of blood in the lacunae of the corpus cavernosum, and they 

 believed that they found this obstacle in the compression of the 

 vena pudenda interna against the symphysis of the pubes. Cuvier 

 and Adelon, finding this cause insufficient, surmised that there 

 was a spasm of the veins emerging from the penis, and thus less 

 blood would leave the organ than entered it. But it was soon 

 seen that the simple idea of blood stasis had not any value. 

 Burdach observed that the arteries of the penis in erection pulsate 

 with greater force, and that erection was never obtained by com- 

 plete ligature of the veins of the penis. Erroneous, therefore, is 

 also the theory of Krause and Kobelt, who attributed the blood 

 stasis and consequent erection to the spastic contraction of the 

 ischio- and bulbo-cavernosus muscles. Valentin was of opinion 

 that the contraction of the muscular fibres of the trabeculae pulled 

 apart the walls of the lacunar system of the corpora cavernosa, 

 and thus enabled the cavernous spaces to receive a greater quantity 

 of blood. But Eouget in 1858 successfully combated this 

 doctrine ; he pointed out that the corpora cavernosa as fibrous 

 tubes, whose interior is crossed by muscular divisions stretched 

 from one wall to the other, could only be diminished in capacity 

 by the contraction of the muscles. In proof of this he adduced 

 the effects of electrical stimulation and cold, which produce a 

 diminution in volume of the organ, accompanied by a kind of 

 rigidity different from that which occurs in erection. 



Kolliker (1852) came to the conclusion that in erection there 

 is no contraction, but transitory paralysis of the muscular fibres of 

 the trabeculae of the corpora cavernosa. Milne Edwards (1868) 

 combined Kolliker's view with that of Kobelt on the contraction 

 of the ischio- and bulbo-cavernosus muscles. But M. Schifif (1868) 

 disproved this opinion by a simple experiment. If all the nerves 

 of the penis are cut, the organ becomes engorged with blood 

 owing to neuro-paralytic hyperaemia, but becomes softer than in 

 its normal state. 



The theory of erection first received a true experimental basis 

 with the discovery of the nervi erigentes, made by Eckhard in 

 1863. These nerves arise from the sacral plexus, and in the dog 

 come from the second, rarely from the third, pair of sacral roots ; 

 along the course of the nerves are intercalated some little ganglia. 

 Eckhard found that electrical stimulation of these nerves produced 

 a turgid condition of the penis, which begins at the bulb of the 

 corpus spongiosum of the urethra, advances, and then spreads over 

 the corpora cavernosa of the penis. If one of the corpora caver- 

 nosa be cut transversely, the blood escapes slowly from it in drops, 

 presenting the dark colour of venous blood ; a few seconds after 



