208 THE GERM-PL.\SM 



I have used in another sense. In stating that germ-cells arise 

 from somatic cells in innumerable cases. I referred to the so- 

 matic cells which are situated along the germ-track, the existence 

 of the latter being assumed for this special purpose. De Vries, 

 however, disputes the somatic character of these cells, because 

 he considers that they also contain ' germ-substance.' I should 

 attach slight importance to a mere name, if a very definite idea 

 did not depend on this name, the abandonment of which would 

 lead to confusion. It appears to me to be dangerous to intro- 

 duce a third category of cells — viz., those of the germ-track — 

 between the somatic and the germ-cells. In the first place, it is 

 unpractical to do so, for the appearance of a cell does not reveal 

 to us whether it is situated in the germ-track or not ; and 

 secondly, it would lead to a total confusion of the ideas of 

 somatic and germ-cells ; for, as has been shown in the previous 

 chapters, there are a number of cells in plant- and animal-stocks 

 which are undeniably somatic, and which must therefore con- 

 tain germ-plasm. Since we regard the * blastogenic ' idioplasm 

 of plants and Hydroids as a modification of germ-plasm, we 

 must also look upon a very considerable number of the cells 

 which constitute these organisms as cells of the germ-track, 

 and we should therefore arrive at the absurd conclusion that a 

 soma (body) is not present at all in these cases. The soma 

 nevertheless is present, and a contrast also exists between it and 

 the germ-cells in plants as much as in animals. 



De Vries contradicts himself when he states that a universal 

 ' continuity of the g^rm-cel/s ' exists through the germ-track ; for 

 in other passages he emphasises the fact that germ-cells do not 

 as a rule arise directly from one another (p. 84), and that a dis- 

 tinction must be made between germ-cells and cells of the germ- 

 track. The somatic character of the cells of a fern-prothallus, 

 for instance, cannot be denied, for they function as somatic cells, 

 and at first are all similar in appearance, so far as we are able 

 to observe. But nevertheless some of them are situated on the 

 germ-track, and give rise to male and female germ-cells. 



If de Vries puts aside the whole question of the continuity of 

 the germ-plasm because he is able to prove that germ-cells 

 always arise from cells of the germ-track, it is evident that he 

 must be labouring under a similar delusion to that which induced 

 .Sachs to claim precedence as regards the theory of the con- 

 tinuity of the germ-plasm. Both these observers consider it 



