COURSE OF THE VAS DEFERENS. 151 



According to Vauquelin, the semen masculinum consists 

 chemically, of water 0.90 ; animal mucus 0.06 ; phosphate of 

 lime 0.03; soda 0.01. 



Fig. 161.* Fig. 162.f > 



Descent )f the Testis 



The testis is placed in the foetus nearly in the same situation 

 as the ovarium is found in the female. This is seemingly for 

 the purpose of ensuring its primitive development) which 

 would have been less certain, if it had been from the first 

 lodged in the scrotum, and the spermatic artery obliged to be 

 formed through so long a space to reach it. 

 In the early periods of foetal life, the testis, as before 

 observed, is placed immediately below the kidney of the same 

 side. Between the fifth and sixth months, it is lodged on the 

 psoas muscle. At the eighth month it is found in the scrotum. 

 Its descent is mainly brought about by the action of the 



* A diagram illustrating the descent of the testis. 1. The testis. 2. The 

 epididymis. 3, 3. The peritoneum. 4. The pouch formed around the testis 

 by the peritoneum, o. The pubic portion of the cremaster attached to the 

 lowe*V part of the testis. 6. The portion of the cremaster attached to Poupart's 

 ligament. The mode of eversion of the cremaster is shown by these lines. 

 7. The gubernaculum, attached- to the bottom of the scrotum, and becoming 

 shortened by the contraction of the muscular fibres which surround it. 8, 8. 

 The cavity of the scrotum. 9. The peritoneal cavity. 



f In this figure the testis has completed its descent. The gubernaculum is 

 shortened to its utmost, and the cremaster completely everted. The pouch of 

 peritoneum above the testis is compressed so as to form a tubular canal. 1. A 

 dotted line marks the point at which the tunica vaginalis will terminate supe- 

 riorly ; and the figure 2 its cavity. 3. The peritoneal cavity. 



