186 



that the mentioned apparatus of Haberlandt, sensitive to light and 

 in which the s(arel)-grains are always lacking, might be identical 

 with our static apparatus (provided that in this case it should be 

 unmovable), for both exercise exactly the same influence ujion tiie 

 growth-phenomena in the joints, etc. 



These expositions might serve to show that the hypothesis of the 

 presence of a movable "static apparatus" in the statocyst affords 

 Such a great advantage in the consideration and the grouping of 

 the mentioned auxotonic movements, that it is entitled to be duly 

 regarded as a working-hypothesis of sufficient foundation and further 

 that there is probably in plants (and in animals ?) a general striving 

 towards an increase of stimulation which might later serve to find 

 a furtlier explanation of how these appropiate movements be brought 

 about. 



Leyden, January 23, 1923. 



