( 567 ) 
Point 4. The anatomical structure of the wood is a better argu¬ 
ment for Dixon 19 ) 20 ) than for Godlewski, for as yet it is quite 
impossible to imagine in what way the living elements could really 
exert any successful pumping action. The unidirectional resistance 
without which such an action can hardly be conceived, has never 
been observed, in spite of a careful search for it. 
This argument is therefore no longer always adduced in support 
of Godlewski. 
Point 5. In critical cases the arguments from analogy are hardly 
more valuable than illustrations. I will therefore not discuss them here. 
We see therefore that the arguments which have been advanced 
so far give little support to Godlewski’s theory. On the other hand 
the striking and conclusive result of Strasburger's intoxication expe¬ 
riments is in favour of Dixon and Jolt. If to this be added the 
great convincing power which proofs from analogy exert, when well 
presented (and here Dixon and Joly are much more fortunate than 
their opponents), we may readily understand, that the cohesion theory 
has many supporters. 
There are, however, two facts which are adduced against this 
theory with more success. 
In the first place a second series of experiments by Ursprung* 8 ) 
in which he used ice instead of steam, in order to render part of a 
branch inactive. This series of experiments does not of course suffer 
from the objections which deprived the other series of its argumen¬ 
tative value. The fact, however, that fading only occurs after several 
days, makes the result less convincing. 
Another objection is more important:. 
Point 6. The distribution of pressure in living trees is opposed 
to the theory**). 
In a hanging water-thread the pressure decreases gradually as one 
ascends and the decrease is at least one atmosphere for an ascent 
of 10 metres. In living transpiring trees it has been impossible to 
demonstrate this; jt was found on the contrary that manometers 
placed at different heights up the trunk, behave quite independently 
of one another. Sometimes one shows a lower pressure, sometimes 
the other. 
It is true that objections can be raised against many of these 
measurements of pressure, but some of them in Schwendener’s opinion 
proved positively and undeniably that there can be no question of 
a regular decrease of pressure. For in this case it would be incon¬ 
ceivable, “dass ein Baumstamm der nach 2 —3 Regentagen durch 
Nachsehub von unten etwas wasserreicher geworden, in mittlerer 
