550 MALE ORGANS OF . GENERATION. ' [CHAP. XXXVII. 



but how these are brought about, seems beyond the pale of 

 human knowledge. 



Upon the subjects treated of in the present chapter, the student may 

 refer to Sir Astley Cooper's " Observations on the Structure and Diseases of 

 the Testis " ; Lauth's " MSmoire sur la Testicule Humaine " ; Professor Kol- 

 liker's Microscopic Anatomy, and articles in the "Microscopical Journal"; 

 Hancock, "On the Physiology of the Male Urethra"; Article "Semen," in 

 the " Cyclopaedia of Anatomy and Physiology." 



