The Two Components of Semen 29 



like material secreted by the seminal vesicles (Bergmann and Leuc- 

 kart, 1855; Bischoff, 1852; Hensen, 1876; Landwehr, 1880; Lataste, 

 1888; Pittard, 1852; Stockard and Papanicolaou, 1919), the enzyme 

 however, responsible for the coagulation is absent in the vesicles 

 themselves and comes into contact with the protein substrate only 

 in the course of ejaculation. The first to recognize the enzymic 

 nature of the coagulating agent were Camus and Gley (1896, 

 1899, 1907, 1921, 1922) who named it 'vesiculase'. It was shown by 

 Walker (1910) that the source of the coagulating enzyme in small 

 rodents is the so-called 'coagulating gland', which lies adjacent to 

 the seminal vesicle. The clotting power of the secretion from the 

 coagulating gland is such that 1 part is sufficient to clot 20,000 parts 

 of the seminal vesicle secretion. This quantitative relationship can 

 be demonstrated in vitro by collecting the two fluids separately and 

 then mixing them after suitable dilution (Moore and Gallagher, 

 1930). 



The liquefaction of human semen which follows its coagulation, is 

 also an enzymic process. Fibrinolysin and fibrinogenase, two pro- 

 teolytic enzymes of semen (see p. 1 14), are believed to play a part in 

 this process. 



