258 ' Simpson and Marshall 



The object of tlie present inquiry was to ascertain whether the mechan- 

 ism of erection is present in animals which have been castrated prior to 

 puberty. It is known that erection can take place in castrated adults, at 

 any rate for a considerable time after the removal of the testes, but this 

 may be due to the fact that the accessory generative organs, having once 

 been developed, do not immediately atrophy. 



Our experiments were upon cats. Before proceeding to operate on 

 castrated cats, we successfully carried out two experiments upon normal 

 animals. The following is an account of the experiments : — 



(1) An adult male cat was anaesthetised, tracheotomised, and fastened face 

 downwards. The spinal cord was exposed in the lumbar region, and the 

 dura mater opened. The cord was then transected at the level of the first 

 lumbar segment. The anterior roots of the sixth and seventh lumbar 

 segments, and of the first and second sacral segments, were exposed on each 

 side. The roots were then ligatured and divided between the ligature and 

 the cord. The posterior roots of the same segments were also divided. 

 The anterior root of the first sacral nerve on the left side was then stimu- 

 lated by an induced current obtained from an ordinary induction coil with- 

 out a Helinholtz wire in the primary circuit. The current used was slightly 

 painful on applying the electrodes to one's tongue. The stimulation caused 

 a gradual but distinct erection of the penis, accompanied by a partial 

 ejaculation of semen. Microscopic examination of the latter revealed the 

 presence of living spermatozoa. The erection gradually subsided on 

 shutting off" the current, but it could again be induced on renewed 

 stimulation. The same result was produced on stimulating the anterior 

 root of the first sacral nerve on the right side. 



(2) This experiment was identical with the first. Erection took place 

 as described above, and was almost immediately followed by ejaculation. 

 On microscopic examination the ejaculated semen was found to contain an 

 enormous number of living spermatozoa. 



(3) This experiment, which was upon a castrated cat, was carried out in 

 the same manner, but the result was negative. The animal had been 

 castrated before puberty, and when about half grown ; the extirpated 

 testicles being approximately as large as peas. The weight of the cat on 

 the date of castration (3rd December 1907) was 1130 grams. At the time 

 (jf the stimulation experiment (3rd July 1908) the cat appeared to be fully 

 grown. Stimulation of the anterior roots of the first sacral nerve on either 

 side failed to produce any sign of erection 



(4) This experiment was identical with the preceding, the result being also 

 identical. The cat was castrated on 3rd December 1907, when about half 

 grown, its weight being 1170 grams. The stimulation experiment was on 3rd 

 July, when the cat appeared to be fully grown. There was no indication of 

 any erection. 



(5) This experiment was similar in every way to the last two. The cat 

 was castrated on 3rd December, its weight at that date being 1060 grams. 



