396 ORGANIC GROWTH sec. 



themselves, at first one or two, but afterwards an ever- 

 increasing number, and at last quite a forest of young fronds 

 were growing from the pulpy mass. Examination showed 

 that by far the greater number of the particles had remained 

 fresh and been able to produce adventitious sprouts. 



" This experiment clearly shows how remarkably the 

 thallus of this plant is able to endure external violence, what 

 energy of life resides in even the smallest aggregate of its 

 cells. This is almost sufficient proof that the unit}^ 

 of the organism is contained potentially in each single 

 vegetative cell ; indeed, it ought not to be impossible under 

 suitable conditions to prove the truth of this proposition by 

 direct experiment." 



By experiments on the subdivision of willows, Vochting 

 obtained further results, which led him to the following con- 

 clusions : " In whatever direction we divide the organism (the 

 willow), and to whatever degree w^e continue this subdivision, 

 in every fragment the whole organism lies as it were con- 

 cealed, provided that the fragment contains cambium-cells. 

 If the subdivision could be actually carried so far as to 

 isolate an uninjured cambium-cell, this cell w^ould doubtless 

 be able to reproduce the whole organism." 



Such facts can only be explained in this way : That to 

 each cell of an organism possessing such a power of re- 

 crescence, as to a germ- cell, the properties which the whole 

 organism inherited have been transmitted also by heredity ; 

 and that, further, every such cell, like a germ cell, by inherit- 

 ing the tendencies of growth and the general formative 

 powers of the ancestors, has acquired the capacity of growing 

 ai^ain into a whole organism. 



The higher such an organism stands in the scale, so much 

 the more formative capacity must it have inherited — the 

 willow more than the Lunularia, — and in a series of species 

 directly descended from the same ancestors in a straight line, 



