410 BIOLOGY: GENERAL AND MEDICAL 



ing from the inferior stock into the superior scion effect 

 any change in it, or will the returning sap from the scion 

 descending into the stock modify it? In the event of the 

 scion's being but one of many branches of the same plant, 

 will the products of the scion descending into the stock 

 and then returning to the other branches modify them? 



It seems difficult to get at the exact facts. As has 

 been said, the ancients believed in these modifications 

 and laid great stress upon them. Some modification 

 would be consistent with what has been found in certain 

 cases of grafting among animals, as when the graft of 

 negro skin becomes white by removal of its pigment, etc., 

 not with others, as the retention of their relative specific 

 characteristics by the anterior and posterior halves of a 

 frog developing from a tadpole composed of halves 

 derived from different individuals of different species. 



The subject has been carefully considered by Daniel, 

 who concludes that, "To say that no variation takes 

 place in the graft is the mistake of the moderns; to 

 believe that variation is constant, regular, and capable 

 of any modification is the error of the ancients. The 

 truth is to be found between these two equally exag- 

 gerated opinions." 



As the result of his survey of the subject and of his 

 own interesting experiments, Daniel came to the con- 

 clusion that "the graft does influence the general nutri- 

 tion of the plant, and that its influence is manifested: 



"1. By modifying the dimensions of the vegetative apparatus 

 of the subject and of the graft. 



"2. By modifying the taste and the size of the edible parts, 

 their chemical composition, and the time of their appearance upon 

 the plant. 



"3. By modifying the rapidity with which the reproductive 

 organs appear upon the graft. 



"4. By modifying the relative resistance of the two plants to 

 parasites and to external agents. 



"The physiological copartnership seems to be entered 

 into upon restricted lines. The general structure of the 

 scion and the stock remain unchanged: each has its own 



