THEORY OF GERMINAL CONTINUITY 49 



be considered to have descended directly from a part of 



the stirps of each of its parents, but then the personal 



structure of the child is no more than an imperfect 



representation of his own stirp, and the personal structure 



of each of the parents is no more than an imperfect 



representation of each of their own stirps." 



Here it will be seen that there is a definite expression of the 



notion that the germinal cells of the offspring are in very direct 



continuity with those of the parents. The antithesis between 



the " soma " and the chain of germ-cells is emphasised. 



Nussbaum. The history must also include Nussbaum, who 

 called emphatic attention to the very early differentiation and 

 isolation of the sex-elements to be observed in some cases. The 

 theory both of Jager and of Nussbaum is that of a continuity 

 of germinal cells. The theory of Weismann is more strictly 

 that of the continuity of germinal protoplasm. The position of 

 Jager and Nussbaum may first be summarised more definitely : 



(1) At an early stage in the embryo, the future reproductive 



cells of the organism are distinguishable from those 

 which are forming the body. 



(2) The latter develop in manifold variety, and lose almost 



all likeness to the mother germ. 



(3) The former the reproductive rudiments are not im- 



plicated in the differentiation of the " soma," remain 

 virtually unchanged, and continue the protoplasmic 

 tradition unaltered. 



(4) The sex-cells of the offspring being thus continuous with 



the parental sex-cells which gave rise to itself, they will 

 in turn develop into similar products. 



Now this fact of continuity of reproductive elements is 

 obviously most satisfactory. If a fertilised egg-cell has certain 

 characters, x t y, z, it develops into an organism in which these 

 characters x, y, z are expressed ; but, at the same time, the 

 future reproductive cells are early set apart, retaining the 



