4 
JOURNAL ON THE ROYAL HORTICULTURAL SOCIETY. 
ideas dependent on them must follow. I do not now concern 
myself with these; my present subject is the descent of the sap, 
and I respectfully suggest to the committee that they could not be 
more usefully or appropriately employed than in giving an authori¬ 
tative expression of their opinion upon it. I do not ask, and 
indeed I would rather deprecate, a hasty, off-hand judgment on the 
spur of the moment, which in any view could only he regarded as 
the expression of individual opinion. What I would like to get is 
a deliberate, well-considered opinion after mutual consultation by 
the most eminent physiologists of our body. 
[2nd Paper.—Read 17th July, 1877.] 
Before entering on the subject of this paper, it may be useful to 
mention—not for this Committee, but for the benefit of the outside 
world who may read the paper elsewhere—that they will find an 
excellent account of the present state of scientific opinion 
on the various questions connected with the sap, which I am 
about to discuss, in a series of papers that were published by Dr. 
Masters in the columns of the “ Gardeners’ Chronicle” in 1874. 
On some he expresses himself with hesitation, on others with more 
confidence, on none with dogmatism, but on all he gives the full 
gist of the opinions generally received at the date of his writing. 
"With this premise I would recall to the memory of the Com¬ 
mittee that at the beginning of this session I drew its attention 
to the course of the sap, being of opinion that recent researches 
rendered some modification in our views necessary on that subject. 
The proposition that I submitted to the Committee was, pure and 
simple, that there was no such thing as descent of the sap at all, 
but that its course was always upwards. I obtained no collective 
expression of opinion from the Committee, but from the individual 
remarks of its members I gathered that they were quite in 
accord with me, so far as regarded anything like circulation. 
I think most of them, if not all, repudiated any belief in the 
old theory of the ascent of the sap by the fibro-vascular bundles of 
the wood and its descent by the cellular layers of the inner bark ; 
but I found the majority still imbued by the theories of Sachs, and 
holding with him, and on his grounds, that descent by some means 
was absolutely necessary, in respect that assimilation could only 
take place in the light, and consequently that the whole of that 
