CHEMICAL PHENOMENA IN LIFE 



preparing for the resting state. Plasmolysed 

 protoplasm has the same inclination. We see 

 that protoplasm in rest has the tendency to 

 diminish its surface as far as possible in 

 proportion to its mass or its volume. The 

 spherical surface is the geometrical minimum of 

 surface for a certain volume. From this pheno- 

 menon we learn that the force of surface tension 

 must in some way regulate the outlines of living 

 protoplasm. When the living protoplasm of an 

 amoeba stretches out its so-called Pseudopodia 

 on one side, and draws in the projecting parts on 

 the other, thus creeping slowly over the moist 

 ground, variations in the surface tension on 

 different parts of the circumference of the cell 

 must take place. The surface tension must increase 

 when new prominences are formed, and surface 

 tension must diminish whenever Pseudopodia 

 are drawn in. But such alterations in surface 

 tension presume certain chemical changes in the 

 boundary layer of the cell, and formation of 

 substances which show different surface tension in 

 comparison with the foregoing state. We learn, 

 further, that such chemical processes must be 

 reversible, to be repeated whenever needed in cell 

 life. In water protoplasm always shows a dis- 

 tinctly lower surface tension to the watery medium 

 than mucous protein substances or carbohydrates. 

 It always rounds to spherical shape when in 

 rest. 



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