208 BOTANICAL GAZETTE [MARCH 
widely different chemical substances, and furthermore, since sub- 
stances deposited as crystals within the sheaths were without effect 
in this respect, KLEBs concluded that the swelling did not depend 
on the chemical nature of the precipitated substance, but did 
depend on the size of the particles composing the precipitate. He 
was led by these and other considerations to the view that the 
presence of solid particles between the particles of the gelatinous 
sheath was the mechanical cause of processes which ended in the 
breaking-off of the jelly along with the precipitate. He described 
this result as being brought about by two steps: first, the particles 
which were precipitated within the sheath slipped out, surrounded 
by portions of the jelly, and gathered at the periphery, where they 
were cemented together by the jelly into a layer surrounding ea 
filament; second, this layer containing the precipitated particles 
was raised up in irregular forms and thrown off by the swelling of the 
jelly. He concluded that the swelling was not due to a reaction of 
the protoplasm to a stimulus, that substances which affected the 
protoplasm also affected the structure of the jelly and consequently 
its capacity for swelling, but that the observed phenomena were not 
then explainable in their molecular-physical relation. 
On grounds of physical chemistry, as has already been suggested, 
it seems possible to bring such phenomena as those observed by 
Kxess and those of the present studies into the same category with 
many cases of enzymatic catalysis. Disintegration of cell walls in 
plants, related to enzyme action, is frequently accompanied by such 
alterations in the material of the walls as to increase the extent of 
their imbibing power, so that they swell much more than is usual 
and assume a gelatinous or mucilaginous consistency. That some 
colloidal metals (as platinum) may exert influences upon organic 
material, that are quite similar in many respects to the effects of 
enzymes, is now generally held. Furthermore, the acidity °F 
alkalinity of the medium employed is well known to influence 
greatly enzymatic catalysis, some enzymes being more effective in 
an acid and others in an alkaline solution. That enzymes are char- 
acteristically colloid and that their activity is closely related to this 
fact seems also to be established by the work of many biochemists- 
The possibility is suggested, therefore, that the disintegration effects 
