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 esculentum) on tobacco 

 (Nicotiana 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 

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



35 



