1895.] The Symbiosis of Stock and Graft. 619 
white and yellow spotting of variegated leaves is unquestion- 
ably pathological and is readily transmitted by grafting. 
Since we do not know the cause of this disease, we can form 
no definite idea as to its method of transmission, yet the whole 
process of transmission gives the impression of an infection. 
How this takes place we do not know, but it seems as if it 
must be through the wandering of specific material particles 
out of the variegated cion into the stock. Concerning the 
transmission of non-pathological peculiarities such as colors, 
especially those held in the cell sap, the author thinks that 
they cannot pass directly into the stock, but that something 
must pass that is able to produce them. He saw in Bonn, 
Lindemuth’s experimentin which violet color was transmitted 
from a potato cion to the green stock, and says it was so. 
His own experiments are as follows: Coleus. Many experiments 
with characteristic forms. The unions were easily affected 
and the plants were kept into the second year and some into 
the third year. Conclusion: In no case was there any trans- 
mission of color from the graft to the stock, or from the stock 
to the graft. Neither was there any influence on the form or 
nervation of the leaves. Cion and stock retained their origi- 
nal peculiarities unchanged, Tradescantia : The shoots of T. 
zebrina and T. quadricolor were grafted on the green T. 
Sellowi. The cions reached a considerable length but in 
no case was there any transmission of color. Beets (salad, 
fodder, and sugar): (a) Union of different colored beets. Dr. 
A. Maclean of Colchester, England, was the first to try this 
in 1853. He joined the root of a red beet to that of a white 
Silesian beet. They united but the red part remained sharply 
delimited from the white. There was no transmission of 
color or of form. In the author’s own experiments white and 
orange, white and red of various shades, and yellow and light 
and dark red beets were united. In part of the experiments 
= roots were joined to roots; in others shoots, to roots. With one 
exception there was no transmission of color from cion to stock 
or vice versa. Each part retained its own color. The blend- 
ing of colors did not occur even in the region of the union. 
Microscopic examinations were made and the place of union 
