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THE AMERICAN NATURALIST [Vol. LVI 



the colloidal state, and at the same time its surface-ten- 

 sion became somewhat different from that of the sur- 

 rounding water. With the assumption of the colloidal 

 state, the electric charges on the colloidal particles would 

 produce the efifect of adsorption and fresh ions would be 

 attracted from the surrounding medium, producing a kind 

 of growth entirely physical in character. We thus ar- 

 rive at the conception of a mass of colloidal plasma dif- 

 fering in surface-tension from the water and increasing 

 in size by two processes, the one chemical, due to linkage 

 of carbon atoms; the other physical, brought about by 

 the adsorption of ions by the colloidal particles. 



The difference of surface-tension would tend to make 

 the surface a minimum and the shape of the mass spher- 

 ical. On the other hand, maximum growth would demand 

 maximum exchange with the surrounding medium, and 

 hence maximum surface. From the antagonism of these 

 two factors, surface-tension and growth, there would fol- 

 low, firstly, the breaking up of the mass into minute par- 

 ticles upon the slightest agitation, and, secondly, changes 

 of form wherever growth involved local alterations of 

 surface-tension, which changes of form would represent 

 the first indication of the property of contractility. 



So far we have considered only the process of the 

 building up of the elementary plasmic particles, the 

 anabolic process. Church, whose memoir already re- 

 ferred to I am now closely following, points out that 

 these anabolic operations must from the beginning have 

 been subject to the alternations of day and night, for dur- 

 ing the night the supply of external energy is removed. 



If during the night," he asks, " the machine runs down, 

 to what extent may it be possible so to delay the onset of 

 molecular finality that some reaction may continue, at a 

 lower rate, until the succeeding day! " And his answer 

 is: ''The successful solution of this problem is defined 

 physiologically by the introduction of the conception 

 ' kataholism,' as implying that energy derived from the 

 ' breaking down ' of the plasma itself . . . may be re- 

 garded as a ' secondary engine, ' functional in the absence 



