632 STUDIES IN GENERAL PHYSIOLOGY 
in contact with a solid body, while, in an Antennularia a 
change in the position of the polyp toward the vertical 
suffices to bring about this result.’ 
While these processes are going on, the material of the stem 
begins to creep or grow out of the original periderm. It 
seems to me worth while to 
call the attention of the 
reader to the fact that in this 
case the process of growth is 
identical with the process of 
progressive motion of a pro- 
Ste toplasmic mass. In plants 
FIG. 155 Sq growth occurs mostly near the 
apex of an organ. If we look 
at the increase in size of the 
stolon from the point of view of growth we notice that its growing 
point is near the apex, just as in plants. But if we look at it 
from the point of view of progressiveamceboid motion wenotice 
that only the foremost point creeps and that the rest of the pro- 
toplasm is pulled out more passively. That the protoplasm 
of the stem is under a strain will be seen by a glance at 
Figs. 152, 153, 154, and 156. The ccenosare or protoplasm 
lies in the periderm in the same way as a stretched rubber 
thread would lie. Wherever the periderm is bent the proto- 
plasm touches it on the concave side. It follows as nearly 
as possible the shortest line in the periderm. It is possible 
that the strain under which the ccenosare is kept causes the 
protoplasm to flow in the direction of the strain toward the 
tip of the stolon. Botanists are inclined toward an ex- 
clusively osmotic conception of the process of growth. I 
have come more and more to the conclusion that the osmotic 
theory of growth is not in harmony with the phenomena 
1In former papers I have described the fact that in Eudendrium the polyps 
are thrown off when the stems are put into small dishes. Such phenomena may 
occur also in Campanularia, but this was not the case here. [1903] 
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