HEREDITY 



545 



ical and artificial. The protoplasm remains unaltered by 

 the act of separation, reduction divisions are not involved, 

 and the inheritance, except in bud-variations, is unaffected 

 by the change. This is evident in those cases where the 



Fig. 404.^ — -Graft of tomato {Lycopersicum esculcnlum) on tobacco 

 {Nicoiiana tabacum). On the tomato are grafted Solanum nigrum, S. 

 integrifolium, and Physalis alkekengi. Cf. Fig. 243. (Graft made by 

 Mr. M. Free.) 



isolated piece is grafted upon another plant; the specific 

 or varietal characteristics of the scion are seldom, if ever, 

 affected by the stock. Thus, in the experiment illustrated 

 in Fig. 404, a tomato stem was grafted upon a tobacco 



35 



