647 
the Ascent of Water in Trees. 
these observers prove that water can travel in the cell-walls of branches 
the wood of which has had its lumina injected with paraffin, their 
paper fails to suggest what relation, if any, this property of the cell- 
walls bears to the upward passage of water in the lumina under 
normal conditions. It seems to me that it may be fairly demanded 
of any proposed theory on this subject, that it should explain the 
relation between the characteristic physical properties of the walls of 
the wood-vessels and the passage of water through their lumina, more 
especially with reference to the question as to whether or not imbibed 
cell- wall may be regarded as maintaining continuity of liquid between, 
say, the upper and lower portions of a tracheide, the central portion of 
which is occupied by a bubble of air. However, it is to be hoped that 
some light will be thrown on this point in the course of Professor Joly’s 
contribution to this discussion. 
Professor Joly read the following paper : — 
I deem it necessary to preface any contribution which Mr. Dixon 
and I may make to this discussion by some remarks of the nature of 
claims to priority. Claims to priority are distasteful writing and 
distasteful reading, and I will hurry over them. I, at the same time, 
ask your indulgence as one acting under obligations which may not 
be shirked. 
Our paper On the Ascent of Sap 1 was received by the Royal Society 
on October 16, 1894, and read November 15, 1894. It was written 
before the Abstract 2 , which appeared November 15, 1894. 
A considerable portion of our paper was excised by desire of the 
Publication Committee of the Royal Society ; and after many delays 
it appeared in the Philosophical Transactions with the note ‘Revised 
April 20, 1895,’ at the head of it. 
A restatement of the principal matter in the Abstract from the pen 
of Professor Askenasy 3 , appeared February 12, 1895; about four 
months after our complete paper was received by the Royal Society. 
Professor Askenasy’s paper is prefaced by the remark that its publi- 
cation was hastened by the appearance of our Abstract. The writer 
admits he had made no researches of his own upon the subject, and 
accounts for his inactivity by the statement that he had considered 
1 Philosophical Transactions, Vol. 186 (1895) B. 
2 On the Ascent of Sap (Abstract), Proc. R. S., Vol. lvii, No. 340, Jan. 1895. 
3 Ueber das Saftsteigen, Heidelberg, 1895. 
