434 
ALFRED DACHNOWSKI 
culence of certain species) is not a function of mere water consumption, 
i. e., of the rate of supply of water to loss by transpiration; nor can it 
be determined solely from a morphological examination of the struc- 
ture of the shoot of plants. Transpiration is not primarily the cause 
of growth. The two are frequently associated and may at times lie 
so closely together that they give the impression of running parallel 
with each other in a causal relation. In such cases transpirational 
values are the consequence of growth e. g. in leaf surface. The processes 
of the absorption of water and that of dissolved substances are not 
identical but independent of each other. 
Another line of evidence in proof of the conception of the chemical 
changes induced through acids and alkalies and thus reducing or 
increasing the quantity of retained water, is apparent from a com- 
parison of the differences in the loss of tissue substances or the increase 
of it by plants under these conditions. The degree of the conversion 
of colloidal and other cell constituents is paralleled by a change in 
their affinity for water which is retained from any available source. 
The water content of the plants is essentially dependent not only 
upon the catalytic action of an optimal concentration of acid or alkali 
but also upon the chemical character of the body material affected. 
The changes that occur in the cells and tissues may be still further 
retarded or hastened through the addition of salts. 
The results of the experiments described in the foregoing pages 
show that the reactions obtained from the addition of salts to toxic 
acid or alkaline solutions rnay aid in developing further the conception 
of antagonistic relations among salts. It is not proposed to discuss 
the views which have been suggested from time to time in regard to 
the causes of this phenomenon or the manner in which salts correct 
injurious effects. The effects may be due in part to depression of 
ionization (ii), or to the formation of undissociated salts (2). The 
valence of ions (12) or their lowered rate of absorption (19) and 
adsorption (16) may determine the action, and it may be referred to 
complicated changes in the permeability of the plasmatic membrane 
of the cells of plants (13, 15), or to the effect of the salts upon protein 
compounds (9, 10, 20, 21, 14). The results here reported make it 
probable, and the conclusion seems unavoidable, that no one of the 
various hypotheses advanced seems to consider the quantitative 
changes taking place in the material and the energy system within the 
cells, whereby the contents become altered in their water retaining: 
