150 PHYSIOLOGY CHAP. 



raise the trunk of the animal into a vertical position to see the 

 penis become erect and, after more or less prolonged mechanical 

 excitation, to witness emission of the seminal fluid. The same 

 fact had already been observed by Brachet many years before (in 

 1839). More recently L. E. Miiller (1902) has observed that 

 the reflexes of erection and ejaculation are preserved even after 

 extirpation of all the lumbar and the upper portion of the 

 sacral region of the spinal cord. It is only necessary that the 

 conus and epiconus medullaris should remain intact. On the 

 other hand, it is noted by pathologists that in man incapacity of 

 erection is connected with diseases of the terminal segments of 

 the spinal cord (Clemens and others). 



But although from these experiments and clinical observations 

 it follows that the integrity of the lower sacral segments is 

 necessary for erection and ejaculation, it is not demonstrated in 

 an adequate manner that the nerve-cells contained in these parts 

 represent the central organ for those functions. The possibility is 

 not excluded that only the most important nerves of the reflex 

 come from the terminal portion of the spinal cord, and that the 

 true centre is represented by the sympathetic ganglionic elements of 

 the sacral plexus. This is the opinion maintained by L. E. Miiller 

 as the result of experiments on animals and observations on 

 man. 



It is certain, however, that the brain and the whole of the spinal 

 cord, although they do not contain the true, immediate centres of 

 erection and ejaculation, are capable of influencing and determining 

 these acts. For it is known that simple psychic representation in 

 the ambit of the sexual sphere, evoked either by the imagination, or 

 aroused by stimulation of the sense of sight, hearing, and especially 

 the olfactory sense, is sufficient to cause not only erection but also 

 ejaculation ; and this occurs independently of any stimulation 

 whatever of the cutis of the penis or the mucosa of the glans. On 

 the other hand, one can easily cause erection experimentally in 

 animals by applying the electric current to the highest segments 

 of the spinal cord, the bulb, the cerebral peduncles, the pons 

 (Budge, Eckhard, 1863). From an old experiment of Segalas 

 (1835), which has been several times confirmed, it is known that 

 puncture, crushing, or destruction by a metallic probe of any small 

 portion whatever of the spinal cord is sufficient to cause erection 

 and ejaculation in a guinea-pig. Numerous are the cases cited in 

 old medico-legal literature of the occurrence of erection of the 

 penis and ejaculation of the semen in men executed by hanging or 

 decapitation. These records were collected, discussed, and confirmed 

 experimentally by Goltz in 1898. Spina, experimenting on guinea- 

 pigs, often obtained the same phenomena by simple transverse 

 section of the spinal cord, and the more surely the lower the 

 section, that is the nearer to the true centre of the reflex. 



