CONTINUITY OF THE GERM-PIASM 415 



plasma {Keim plasma), which the parental ovum con- 

 tains, is not used up in the formation of the offspring, 

 but is reserved unchanged for the formation of the 

 germinal cells of the following generation." 



(2) What is actually continuous is the germ-plasm — " of 



definite chemical and special molecular constitution." 

 A continuity of germinal cells is now rare ; a continuity 

 of intact germinal plasma is constant. 



(3) This germ-plasm has its seat in the nucleus, is extremely 



complex in structure, but has nevertheless an extreme 

 power of persistence and enormous powers of growth. 



(4) " The germ-substance proper must be looked for in the 



chromatin of the nucleus of the germ-cell, and more 

 precisely still in those ids or chromosomes which we 

 conceive of as containing the primary constituents of a 

 complete organism. Such ids in larger or smaller 

 numbers make up the whole germ-plasm of a germ-cell, 

 and each id in its turn consists of primary constituents 

 or determinants, i.e. of vital units, each of which 

 determines the origin and development of a particular 

 part of the organism." 



(5) "The spUtting up of the substance of the ovum into a 



somatic part, which directs the development of the 

 individual, and a propagative part, which reaches the 

 germ-cells and there remains inactive, and later gives 

 rise to the succeeding generation, constitutes the theory 

 of the continuity of the germ-plasm which I first stated in 

 a work which appeared in the year 1885 " (1904, vol. i. 

 p. 411). 



