20 BOTANICAL GAZETTE [JANUARY 
properties of the soil toward chemical compounds which form a 
demonstration experiment in the usual elementary course in plant 
physiology is in considerable part a demonstration of adsorption. 
Indeed, the whole relation of the plant to its soil environment is 
very largely influenced by this factor. 
It is also probable that in the internal processes of the plant and 
of the animal, similar forces are in operation, influencing, together 
with diffusion and osmosis, the movements and distribution of mole- 
cules and ions within the organism. For example, it would appear 
not at all improbable that in cells containing starch grains or other 
undissolved substances, the distribution of the various molecules and 
ions of the cell sap is to no insignificant degree influenced by adsorp- 
tion, and the transfer of molecules or ions from place to place may be 
modified by this tendency of the walls, starch grains, and other porous 
but insoluble substances to attach to themselves condensed layers of 
molecules or ions. Indeed, it would be easy to see in a speculative 
way many directions in which the processes of life may be affected 
by the form of activity demonstrated in the above experiments to be 
in operation under certain common conditions. 
In nature the roots themselves and other absorbing organs fein : 
surfaces for adsorption and the layer of solution about them is molec- 
ularly more dense than the free solution. This applies in a much 
greater degree to minute, submerged forms of life, as bacteria. 
Absorption into the cell takes place, therefore, in general from a _ 
denser layer at the surface of the organism by the continued operation 
of the energy of ad ion. This surface layer is continually renewed, 
resulting in an ada absorption. 
Another relation of importance is seen in the size of the organism. 
The more minute, the greater would be the efficiency of adsorptive _ : 
activity. This may aid in accounting for the extreme efficiency of the 
‘minuter forms of life in operating on their medium. 4 
Many suggestions occur as to divers other ways in which adsorp a 
tion may play a part 1 the lives of living th oe 
but to give them value the accumulation of more evidence is necessary a3 
Further studies in this direction are in progress. a. 
U. &. Dewan or AGRICULTURE, Washington, D. = and et Mu a 
Universiry, —— Tl. 
