384 GENETICS IN RELATION TO AGRICULTURE 
fruits, Baur states that there are varieties of eggplant which occasionally 
bear tomato-shaped fruits even when not grafted, and that Daniel 
probably used such a variety. Again Daniel and Elder have reported 
experiments tending to show that the seedlings of scions exhibited an 
influence of the stock. Baur is inclined to think that accidental cross- 
pollination must explain such cases. But Daniel has recently reported 
similar results when working with different varieties of beans. In this 
case, however, there is the possibility that the seedlings of the scions 
and the seedlings used for comparison, which were from ungrafted plants, 
belonged to different pure lines. Thus in some such simple manner all the 
supposed cases of transference of morphological characters may be 
explained. 
Regarding the actual transference of the chemical constituents of the 
tissues from stock to scion and vice versa, the results of experiments 
differ with respect to different plant ingredients. Thus, according to 
Guignard, glucosids do not pass from one graft component to the other 
when the two contain different kinds of glucosids, and the glucosids 
present in plants are apt to differ unless the plants are closely related. In 
eraft-symbionts whose components belong to different species, Guignard 
thinks that each component tends to retain its own chemical properties. 
On the other hand, Meyer and Schmidt found that alkaloids such as 
nicotine will pass from a tobacco scion into a potato stock. This is a 
promising field for future investigation. 
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