120 Theory of the Germ-Plasm 



ginning of autumn, when left by their inhabitants, they 

 are still quite turgescent. If they are now buried in hu- 

 mus, they will keep through the winter, and can even 

 enter upon a new life in the following summer. They will 

 then form new chlorophyll, by means of which they are 

 nourished, and the best among them will gradually begin 

 to put forth adventitious roots. These originate either on 

 the outer or on the inner surface of the wall surrounding 

 the cavity, and are always located on the vascular bundles 

 of the gall. Judging from their microscopic structure, 

 these rootlets, reaching a length of a few centimeters, are 

 identical with the normal young roots of the respective 

 species of willow. The required hereditary characters 

 must therefore be present in a latent state in the gall, in 

 which probably nobody would otherwise have looked 

 for a germ-track. 



These important experiments will become still more 

 instructive for our purpose, when we shall succeed in mak- 

 ing the gall-roots develop so far that they are enabled to 

 form adventitious buds. But, since the roots of all woody 

 plants have this power, we may predict even now that this 

 experiment will succeed. Perhaps it will require special 

 measures, as for example, a graft on the roots of a willow. 

 But without doubt we may conclude from the complete 

 agreement in the anatomical structure, as proven by Bey- 

 erinck, that the physiological properties also, of the nor- 

 mal and of the gall-roots are the same. 



And if anyone is ever successful in growing in this 

 way an entire willow from a gall, it will be clear, that, in 

 the latter, all the hereditary characters of the willow are 

 present in a latent state. 



This would obviously be much more useless than their 

 presence on any given normal somatic track. The con- 



