170 THE PLANT WORLD. 



this differentiating effect results from the grafting of scions of the 

 pear upon stumps of young plants of the quince. In this case the 

 scion, although taken from a standard tree, produces a dwarfed 

 trees, and the fruit, although true to its variety as regards form, 

 size, color, etc., differs slightly from the fruit of the standard tree 

 from which the scion was taken. But these facts are not at variance 

 with the truth of the statements that have been made nor with those 

 which follow. 



The potential, or latent, existence of the improved fruit-charac- 

 ters of a plant in its stem and branches is proved by the frequent 

 springing therefrom of adventitious buds, which produce branches that 

 bear fruit of the same variety as do branches from the regular axillary 

 buds; and yet those adventitious buds originate from common camljium 

 cells which, but for some accidental cause, would have remained re- 

 prodnctively inert. The latent existence of varietal fruit-characters 

 in the root is proved by the varietal identity of the fruit of certain 

 shrubs and trees, which have originated as suckers, with that of the 

 original })lants from the roots of which they respectively spring. 



The (juestion of how varietal fruit-characters, as well as the 

 distinjiuishino- varietal features of the plant, are transmitted from 

 generation to generation and from one part of a plant to other 

 parts of the same is an intricate and mysterious one, but certain facts 

 concerning it seem to have been clearly ascertained. It is known that 

 every plant is not only of cell origin Itut tiiat it consists throughout of 

 a mass of cells; that the so-called wall of each cell is the partially 

 hardened self-covering of a protoplast or a minute individual mass of 

 protoplasm; that the prot()])lasts, or as is usually said, the cells, in- 

 crease by self division and with great ra})idity, and that the growth of 

 the plant really consists of this rapid and abundant cell division. It is 

 further known that although each cell is distinct it is connected with all 

 adjacent cells in the growing parts of the plant by exceedingl}^ minute 

 filaments of protoplasm, and that the physiological functions of the 

 plant are carried on by the transmission of liquids and gases through 

 and among this complicated colony of living protoplasts. The infer- 

 ence seems to be necessary that all the varietal characteristics of a 

 plant, including its fruit-characters, are also transmitted along these 

 physiological linos, and that every cell in every growing part of the 

 plant receives their influence which it retains, at least latently, so long as 

 it retains vitality. Wherever a bud is formed the entire varietal nature 



