Objections to the Theory 115 



is necessary for the functions of its descendents.^^ If the 

 progeny be unHmited, as in the germ-tracks, then the nu- 

 cleus receives the entire germ-plasm; but since the pro- 

 geny of a somatarchic cell is limited, and since it is 

 restricted in its morphological and physiological range of 

 development, it gets only the corresponding part of the 

 hereditary characters. Therefore they have no true germ- 

 plasm, .but only somatic plasm. 



On the hypothesis of the germ-plasm, Weismann 

 builds that of the ancestral plasm, which is directly op- 

 posed to pangenesis, and has been critically considered 

 in the last division of Part I. But the empirical justifica- 

 tion for the basis of that assumption, may here be con- 

 sidered from every possible point of view. 



That Weismann has not succeeded in convincing bot- 

 anists is shown by the various objections to him, made 

 especially by Sachs and Strasburger. The essence of these 

 objections is that Weismann has not sufficiently consid- 

 ered the secondary germ-tracks, and has thus been in- 

 duced to assume a sharp contrast between germ-plasm and 

 somatic plasm. Now, not only the oft mentioned exam- 

 ple of the begonias, but the entire and very rich doctrine 

 of adventitious buds, teach that there is nowhere a sharp 

 line of demarcation between the secondary germ-tracks 

 and the somatic tracks of the plant. The latter have de- 

 veloped only quite gradually out of the former. And 

 even though they have in fact often lost the power of re- 

 production, everything speaks in favor of the fact that 

 they still very frequently possess it potentially. In other 

 words, the loss of germ-plasm need not necessarily go 

 hand in hand with the loss of the power of reproduction. 



In his book, Ueher Organhildung im Pflanzenreich, 



2Cf. also Part I, Chapter III, 6, p. 53. 



