THE WONDERS OF LIFE 



structure in the large plastidule or biogen as a single 

 molecule. Verworn's biogen-hypothesis seems to me 

 quite satisfactory when it represents the primitive 

 molecule of living matter as really the ultimate factor 

 of life. 



The chief process in the evolutionary history of the 

 plasm is its separation into the inner nuclear matter 

 (caryoplasm) and the outer cellular matter (cytoplasm). 

 When both kinds of plasm arose by differentiation from 

 the originally simple plasm of the monera, there also 

 took place the morphological separation of the nucleus 

 (caryon) and cell-body (cytosoma or celleus). As these 

 two chief forms of living matter are chemically different 

 but nearly related, and as they may in certain circum- 

 stances (for instance, during indirect cell-division and 

 the partial caryolysis connected therewith) enter into the 

 closest mutual relations, we must suppose that the 

 original severance of the two substances took place 

 gradually and during a long period of time. It was not 

 by a sudden bound or transformation, but by a gradual 

 and progressive formation of the chemical antithesis of 

 caryoplasm and cytoplasm, that the real nucleated cell 

 (cytos) arose from the unnucleated cytode (or primitive 

 cell). Both may correctly be comprised under the 

 general head of plastids (or formative principles), as 

 "ultimate individualities." 



I regard as the chief cause of this important differen- 

 tiation of the plasm the accumulation of hereditary 

 matter — that is to say, of the internal characteristics 

 of the plastids acquired by ancestors and transmitted 

 to their descendants — within the plastids while their 

 outer portion continued to maintain the intercourse 

 with the outer world. In this way the inner nucleus 

 became the organ of heredity and reproduction, and 

 the outer cell-body the organ of adaptation and nutri- 

 tion. I put forward this hypothesis in 1866 in my 



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