154 PHYSIOLOGY CHAP. 



of the testicles was communicated by Brown-Se'quard and his 

 collaborators to the Societe de Biologie of Paris between 1891 and 

 1893. He announced that hypodermic injections of testicular 

 extract methodically repeated not only mitigated ueuro-asthenic 

 conditions, but, acting as excitants of the central nervous system, 

 caused the disappearance of the phenomena of sexual impotence, 

 even when they are due to old age ; restoring the power of 

 erection, seminal formation, and ejaculation. 



This announcement much interested the medical profession, 

 amongst whom spread in a short time the practice of injecting 

 testicular juice as a cure for sexual impotence, before the matter 

 could be put on a satisfactory scientific basis. The beneficial 

 effects at first extolled were certainly exaggerated through 

 professional interests, and were due in great part to the effects 

 of suggestion on the patients, for under rigorous experimental 

 control in the laboratory they were not confirmed. 



A series of experiments carried out under strict conditions at 

 Graz by Pregl and Zoth are not, however, wanting in importance, 

 and although conducted on man are free from the influence of 

 suggestion. They studied the action of the testicular juice on 

 muscular work both with the ergographic method and with simple 

 levers, and arrived at the conclusion that the injections alone 

 do not increase the capacity for muscular work, but that associated 

 with daily muscular exercises they conduce to a degree of vigour 

 which with exercise alone it does not seem possible to reach. 

 They saw, besides, that this increase in muscular strength persisted 

 long after the injections of testicular juice had ceased. 



In harmony with this result is also the fact observed by 

 Hedbom on the isolated heart perfused with blood ; the addition 

 of testicular extract strengthened in a striking manner the 

 rhythmical contractions. 



We know nothing of the mode of action of the testicular juice 

 in strengthening voluntary movements, but it appears probable 

 that its action is exercised on the central nervous system. The 

 active principle of the extract has not yet been isolated. Its 

 presence in the organised constituents of the testicles may be 

 excluded, for the extract which is used is subjected first to 

 filtration through porcelain, which does not allow the passage 

 of any organised element. When the seminal fluid is slowly 

 dried, there are formed crystals which chemically result from the 

 combination of phosphoric acid with a base, the so-called spermine, 

 of which we have had occasion to speak when considering the 

 prostatic secretion, and the chemical formula of which is C 2 H 5 N. 

 Poehl (1898) sought to attach to spermine all the virtues which 

 had been attributed to testicular juice : he considered it a potent 

 oxygen-carrier, and as such a powerful physiological accelerator 

 and intensifier of exchange of material. The later researches of 



