VISIBLE CONSTRUCTIVE ACTIVITV IX PROTOPLASM. 583 



transmitted to the descendants. lu the next generation of these same plants it is 

 a group of spherical and not of dodeeahedral cells, which arises at the particular 

 place. The latter will, indeed, only reappear if the aforesaid pressures be again 

 exerted. 



How little, however, external influences define the form and grouping of 

 permanent cells, is shown by the fact that from one and the same meristem, under 

 the same pressure, the same temperature, and equal illumination, arise in the closest 

 proximity the most diflferent permanent cells; and that, on the other hand, the 

 formation and grouping of these cells is not essentially diflerent when the develop- 

 ment of the meristem takes place under wholly different external pressure, or 

 different temperature. We always come back to tliis important thesis: — the forces 

 operating on plants from outside are only stiTnuli to the formative processes; 

 these latter are accomplished independently of external influences in a manner 

 established for each species, and founded in the specific construction of its living 

 protoplasm. 



