Effect of Stimulating the Nervi Erigentes in Castrated Animals 259 



The stimulation experiment was on 3rd July. The result was entirely 

 negative. 



(6) In this experiment, which was a control, the first sacral anterior roots 

 of another fully grown normal male cat were stimulated experimentally in 

 identically the same way as in the preceding cases. Erection took place 

 gradually as in the other two control experiments (1 and 2). Ejaculation 

 also occurred, the semen being found to contain numerous spermatozoa, 

 some of which were moving when examined under the microscope. 



The experiments show, therefore, that erection cannot be induced 

 experimentally in animals which have been castrated prior to puberty, or, at 

 any rate, that it is far more difficult to cause erection in such animals. 



It is well known that in animals castrated in early life the secondary 

 sexual characters as a general rule fail to make their appearance, and that 

 the correlation between the testicles and the accessory generative organs 

 is a still closer one. Thus the prostate and Cowper's glands undergo 

 atrophy after castration, even in cases where the operation of removal is 

 performed after puberty.^ It is possible, therefore, that in animals which 

 were castrated when young the muscular apparatus of the penis fails to 

 develop sufficiently to admit of erection occurring, but it would seem 

 unlikely that the nervous mechanism is impaired. If erection is due 

 mainly to an inhibition of the vasomotors of the penis, as is ordinarily 

 supposed, there would seem to be no theoretical reason why it should not 

 be possible to bring about that process experimentally (or at any rate to 

 produce a partial erection) in animals which have been castrated. It 

 would appear, therefore, that the process of erection is very possibly a 

 more complex phenomenon than is generally believed, but our experiments 

 throw no further light on the mechanism of that process. 



' Griffiths, "Observations on the Formation of the Prostate Gland in Man and the 

 Lower Animals," Journ of Anat. and Phys., vol. xxiv., 1890. Wallace, " Prostatic Enlarge- 

 ment," London, 1907. 



VOL. L, NO. 3. — 1908. 18 



