( 564 ) 
remarkable that we must devote some space to examine fully the 
grounds for their contention”. 
When we attempt to trace why opinions diverge so widely, the 
cause seems to lie principally in a different appreciation of certain 
experiments and in the somewhat adventurous aspect which the 
Dixonian explanation presents at first sight. It is necessary to become 
accustomed to the idea that the life of our trees hangs upon a water- 
thread, before we can become reconciled to it. Godlewski x1 ) indeed 
required a much more adventurous hypothesis in order to reconcile 
the anatomical structure of the wood with its power of pumping up 
water. This part of his theory has in consequence received adhesion 
from no one and so I will leave it out of discussion. In what follows 
below, “Godlewski’s theory” will therefore mean the view that the 
living wood must be regarded as the cause of the transpiration current. 
In order to facilitate a judgment of the state of affairs I will 
tabulate the most important arguments of the two parties side by 
side and will then discuss them in pairs. From this table I omit 
everything relating to the question whether the cohesion of water 
is sufficiently great to account for the work which Dixon and Joly 
attribute to it. I will assume, if I may put it thus, that there is no 
technical objection to their theory and l think this assumption may 
be made with safety. 
Godlewski c. s. Dixon and Joly. 
la. There is not sufficient con¬ 
tinuity in the water columns of 
the wood to admit cohesion as an 
explanation 12 ). 
lb. There is no reason for 
doubting the continuity of the 
water columns “). 
2 a. The remaining available 
physical forces are insufficient to 
raise the water more than 14 
metres 14 ). 
2b. Strasrcrger’s experiments 
in which the water ascended in 
poisoned trees, prove the con¬ 
trary 15 ). 
The cohesion theory has at its 
disposal forces which would be 
able to provide a tree of 200 
metres and more with water 1 *). 
3 a. Ursprcng’s experiments, with 
branches which had been killed for 
part of their length, after which the 
36. In Ursprung’s experiments 
the conduits become blocked and 
the leaves were poisoned because 
