546 MALE ORGANS OF GENERATION. [CHAP, xxxvil. 



performed, the tubes are seen to be entirely occupied by cells, in 

 which the spermatozoa are ultimately developed. 



When semen is about to be formed, the following changes may 

 be observed to take place in the epithelium. 



The cells become detached from the basement membrane, in- 

 crease in size, and assume a more spherical form, the contents at 

 this time being entirely granular; at length, however, several 

 clearer points or nuclei are seen in the interior of the cell, which 

 is now passing down the tubule towards the vas deferens, while it 

 is succeeded behind by the formation of new cells. The nuclei 

 in the interior enlarge, and are often seen to contain nucleoli. 

 The parent cell, having much increased in size from the develop- 

 ment of its nuclei into cells, appears to undergo no further change; 

 but in each of the contained cells, which vary much in number, 

 one spermatozoon is developed on the inner wall, in the form of 

 a spiral filament, as was first described by Kolliker. The sperma- 

 tozoon escapes into the interior of the mother cell by the rupture 

 of its development cell. Others are in like manner set free; 

 and they arrange themselves in a parcel, which may ultimately 

 consist of a vast number of separate spermatozoa, with all the 

 heads arranged in one direction and the tails in the opposite 

 one. 



The cause of this arrangement is probably somewhat similar to 

 that which determines the blood discs to run together, and assume 

 the form of a small pile of coins. There appears to be a sort of 

 attraction existing between the different spermatic filaments for 

 each other. The contained spermatozoa are at last set free by the 

 rupture of the parent cell, and then separate. These changes are 

 usually not completed until the cells arrive at the epididymis ; so 

 that' in the seminal tubules cells alone are found, while in the vas 

 deferens we only meet with perfectly developed spermatozoa. 



Spermatozoa. The spermatic filament or spermatozoon of man, 

 is a perfectly clear hyaloid filamentous body, in which a dilated 

 portion, termed the body or Jiead, may be observed, from which is 

 prolonged a long tail or filament, which gradually tapers to an ex- 

 tremity which is hardly visible from its extreme tenuity. The 

 head or larger extremity is flattened from side to side and of a 

 conical form, the pointed extremity being anterior. The length of 

 the spermatozoon is about g^th of an inch, and the width of 

 the body in one direction about the 3-oVo tn > and not more than 

 the To-^th of an inch in the opposite. The tail varies somewhat 

 in length in different specimens. 



