136 



PHYSIOLOGY 



CHAP. 



of spermine (which are absent in the living), to which, as we have 

 remarked, the semen owes its characteristic odour. 



Fiirbringer has succeeded in obtaining the prostatic secretion 

 of man during life. By pressure on the prostate, the glandular 

 contents are expelled and collect in the urethra, from which they 

 can be removed. The secretion has the capacity of effecting move- 

 ment in the spermatozoa by some special action, and not only 

 by acting as an indifferent liquid which dilutes the semen. In ex- 

 cessive quantity it proves harmful to their vitality, probably owing 

 to the development of an acid. This property of activating the 

 spermatozoa does not belong inclusively to the prostatic secretion, 



FIG. 29. Section of prostate of adult man. Magnified 45 diameters. (Sobotta.) ts, tubules and 

 glandular vesicles ; TO, bundles of smooth muscular fibres of the stroma. 



but also, as we have noted, to the secretion of the epididymis 

 (specially of the ampulla). In fact, spermatozoa collected directly 

 from the epididymis of the guinea-pig move in as lively a manner 

 as those which have been subjected to the influence of the 

 prostatic secretion (Exner and Nagel). Fiirbringer, however, 

 maintains that the prostatic secretion renders these movements 

 more active. Steinach observed that the spermatozoa of rats 

 continue to move for a longer time when a little sodium chloride 

 solution is added to the prostatic liquid. 



Walker (1899) carried out a systematic series of researches on 

 the sperm of the dog, and arrived at the following conclusions : 



(a) The sperm drawn from the testicles shows no active 

 movements. 



