. The dynamics of living matter . FIG. 9.—AFTER BUTSCHLI. podium. According to Berthold,* the phenomena of streaming in the interior of an Amceba in the process of the formation of a pseudo- podium are such as to agree with the ideas of Quincke. Biitschli has come to the same conclusion. It seems to me, however, that if it is true that the Amceba is covered with a solid surface film, one condition for the formation of a pseudopodium must be a local liquefaction of protoplasm. In consequence of such a liquefaction, new protoplasm must flow out, which, subsequently, will form a new solid film at
. The dynamics of living matter . FIG. 9.—AFTER BUTSCHLI. podium. According to Berthold,* the phenomena of streaming in the interior of an Amceba in the process of the formation of a pseudo- podium are such as to agree with the ideas of Quincke. Biitschli has come to the same conclusion. It seems to me, however, that if it is true that the Amceba is covered with a solid surface film, one condition for the formation of a pseudopodium must be a local liquefaction of protoplasm. In consequence of such a liquefaction, new protoplasm must flow out, which, subsequently, will form a new solid film at its surface. This may again be liquefied, and a new streaming may occur, etc. Such liquefactions can be caused by lack of oxygen, as we saw in a previous lecture; but they may also be caused by other chemical changes. I am inclined to believe that phenomena of liquefaction play at least some role in these processes of protoplasmic motion. Imbertf published several years ago a hypothesis concerning the contraction of smooth muscle fibers, which assumes that the "stimulus" which causes the contraction of smooth muscles produces an increase in the surface tension between the longitudinal fibrils and the surround- ing liquid of the muscle cell. These fibrils are long and thin cylinders; every increase in surface tension must have a tendency to make these fibrils more spherical, thicker and shorter. Such a change of form occurs indeed during contraction, but it is difficult to understand why the fibrils do not assume this form under the influence of surface tension alone, without stimulation. To meet this difficulty, Imbert assumes that smooth muscle fibers cannot contract unless they are stretched passively. He presupposes that their arrangement in the body is such that this prerequisite is generally fulfilled. Bernstein has tried to explain away some of the weak spots in this The surface energy at the limit between two media is equal to the product o
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