THE STORY OF NINETEENTH-CENTURY SCIENCE 



years by a multitude of observers, and gained currency 

 notwithstanding von Mohl's reiterated contention that 

 there are really but two ways in which the formation 

 of new cells takes place, namely, "first, through divis- 

 ion of older cells ; secondly, through the formation of 

 secondary cells lying free in the cavity of a cell." 



HUGO VON MOHL 



But gradually the researches of such accurate observ. 

 ers as linger, Nageli, Kolliker, Reichart, and Remak 

 tended to confirm the opinion of von Molil that cells 

 spring only from cells, and finally Rudolf Virchow 

 brought the matter to demonstration about 1860. His 



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