10 
JOUKNAL OF THE EOYAL HOHTfCULTUEAL SOCIETY. 
that the properties of the stock affect the scion. They are carried 
up into its system, hut those of the scion are not carried down into 
the stock. If the theory of descent and wandering and mixing of 
the sap were true, the qualities of the scion ought to descend just 
as much as those of the stock ascend, but they do not. But some 
one may say, “Oh, hut you are wrong; there are cases in which 
the influence of the scion has made itself felt on the stock.” How 
many ? I ask. Out of the myriads of grafts that are made every 
year we hear perhaps once in a decade of some single plant where 
there is a doubtful appearance of a scion having had some influence 
on a stock, or, rather, on a shoot from one. How, if I disputed 
the fact altogether of such an influence ever having been truly 
Seen, I think I should have plenty of supporters, and I am not sure 
that I should not be in the right, but I am not careful to do this 
thing. I am willing to take it as possible that such a thing may 
have, and that such a thing has occurred, but I add that it is still 
capable of explanation in accordance with my interpretation of the 
flow of the sap. It will be observed that such cases have never 
been observed until after the lapse of a winter after the grafting, 
and, in fact, it is nearly impossible that they should. How although 
I maintain that there is no descent of the sap, I never did (and 
could not) deny that there is a period (winter) when it no longer 
flows at all. The liquid part of the sap is evaporated, the more 
solid part is dried up, deposited or crystallised, or what is called 
“ stored up ” for next year. I imagine that this takes place pretty 
much simultaneously all through the plant, so that there is little 
sinking of the column of sap in the vessels. But it is possible that 
under conditions when there is an unusually large supply of sap in 
the vessels at the approach of winter, or in plants whose vessels are 
favourably constructed for it, there may be something like a 
disturbance of equilibrium, which will allow the sap to ebb, so that 
a portion of what properly belongs to the scion floating on the top 
of the tide may fall below the graft, and, being there stored up until 
redissolved and carried up next year, may give rise to the doubtful 
phenomenon of which I speak; but I take my stand, not upon 
exceptions, but on the broad basis of an all but universal experience 
throughout the whole world. 
I meant to have stopped here, but I am in the position of a 
man, who, having begun to take a rotten beam out of an old house, 
finds a whole superstructure of dependencies, offsets, and rookeries 
tumbling about his ears. The system of vegetable physiology now 
in credence was built up on the faith of the existence of a circulation 
