238 Protoplasmic Dynamics. [ April, 
that the protoplasm contains, besides oxygen, many other re- 
agents as its stored food-constituents; that there are also more 
of the volatile elements in its composition, which is more com- 
plex while its consistency is that of elastic viscosity. ‘Further, 
the oxidation in organic fluids cannot be so intense and generates 
but a comparatively small amount of heat, so little that it is 
eliminated by conduction without appearing in such vast quanti- 
ties as to induce a boiling or convectional circulation, while the 
chemical reactions of the organized plasma-components are ex- 
ceedingly slow and weak, yielding but little heat. 
The intersusception and interpolation of new matter into the 
plasma is by zmbibition, which also is the method of ingestion of 
nutriment by the plasma of cells and the lowest organisms. This 
imbibition process is a well-established concomitant to all plasma- 
action, but while its value as a nutritive power determining the 
peculiarities of nutrition and growth has been esteemed, its great 
importance in the production of mass-motions has not become 
understood. 
Vi—ZJmbibitional swelling, in some respects, simulates that 
resulting from inorganic absorption and diffusion, but is markedly 
different, especially since the engaged combining powers act 
stronger than those freed, so that it does not result in a dissolu- 
tion or solution of the imbibing substance, while the increase of 
distension intensifies its tension and elasticity. To understand 
the possibility of this swelling without rupture of the chemismic 
bonds in organic bodies, we may have to regard their constituents 
as grouped into filamentous branches or a spongy mesh, in sym- 
metrical order, and remember that they are certainly very com- 
plex, for, according to recent chemical theories, some of the 
albumenoid molecules may contain a thousand atoms. 
Let us now classify the principal kinds of plasma-motion while 
trying to explain how each is attained. 
1. Axial Procession. —Let x—y represent a surface on which a 
a lump of plasma is shown in sec- 
_— Cag tion, the heavy portion of its out- 
| J ine indicating that part of its sur- 
face which is acted on by light or some other decomposing force. 
Imbibition from within to this tract is induced and it swells thereby 
advancing slightly toward the light, while gravity pulls it down $O 
at an ea descending movement of the front’ manget i 2 
