1 1 o Protoplasm. 



the entire theory was expressed in the dictum, 

 " Omnis cellula e cellula? 



The first step in resolution of this theory was 

 the elimination of the investing membrane. 

 Such membrane may and does ultimately form ; 

 but in the first instance, for the most part, the 

 cell is naked. The second step was the elimin- 

 ation, or at least the subordination, of the 

 nucleus. The nucleus is now discovered to be 

 necessary neither to the division nor to the 

 existence of the cell. 



Thus, then, stripped of its membrane, relieved 

 of its nucleus, what now remains for the cell ? 

 Nothing, but that which was the contained 

 matter, the intracellular matrix, and is Proto- 

 plasm. 



The application of the word, however, to the 

 element in question, like the history of the 

 thing, was marked by several stages. First 

 came Dujardin's discovery of sarcode. Then, 

 as above mentioned, Von Mohl's introduction 

 of the term protoplasm as the name for the 

 layer of the vegetable cell that lined the cellu- 

 lose, and enclosed the nucleus. Cohn, four 

 years later, proclaimed "the protoplasm of the 

 botanist, and the contractile substance and 

 sarcode of the zoologist" to be, "if not identical, 

 yet in a high degree analogous substances." 



