DEVELOPMENT OF THE SPERMATOZOA. 153 



very various views that have been expressed in respect to 

 their nature and significance, the rectification of which has 

 been reserved for the present time. 



Kolliker* first demonstrated that the spermatozoa were to 

 be regarded, not as individuals possessed of independent life, 

 but as elementary parts of the organism, and showed their 

 origin in cells. He held that they develop in the nucleus, and 

 subsequently in the cell, within which they for a time lie 

 coiled up, until at length they are set free by the bursting of 

 the latter. 



Reichertf vigorously opposed the views of Kolliker, and, 

 supported by his researches on Strongylus auricularis and 

 Ascaris acuminata, maintained that the spermatozoa originated 

 in elementary nucleated cells proceeding from a cell formation 

 taking place in the entire contents of the mother cells. 



Leuckart J gives the following account of the origin of the 

 spermatozoa. At one time, he says, the entire sperm cell, with 

 all its parts, is converted into a spermatozoon ; at another the 

 spermatozoon proceeds exclusively from the nucleus ; and 

 finally, at another, it originates from the contents of the sperm 

 cells. In the latter case Leuckart explains the vesicles of 

 evolution of the spermatic cells to be, not nuclei, as Kolliker 

 thinks, but cells formed endogenously. The spermatic cells 

 themselves, he believes, originate in a similar endogenous 

 manner from the mother cells. 



A more recent investigation of this point by Kolliker has 

 led him to differ somewhat from his original statement, and 

 he now thinks that the spermatozoa do not originate within, 

 but as an outgrowth of the nucleus, though this can only be 

 correctly stated of the Mammalia. The true sperm cells are 

 partly extremely small cells and partly larger vesicles with 

 many nuclei. The nuclei of these cells and vesicles undergo 



* Beitrage zur Kenntniss der Geschlechts-verhaltnisse uiid der Samenflus- 

 sigkeit wirbellose Thiere, 1841. Die Bildung der Samenfaden in Blaschen. 

 " Essays upon the Sexual Relations and the Spermatic Fluid of the In- 

 vertebrata," 1841. " The Formation of the Spermatozoa in Vesicles." 



t Muller's Jrchiv, 1847, p. 58. 



Handivorterbuch der Physiologic, by Wagner, Band i., p. 851. 



Zeitschrift fur wissenschaft. Zoologie, Band vii. p. 201. 



