Protoplasmic Movement. 



87 



Barber's moist chamber. Release of pressure on the steel tube 

 draws substances into the pipette. Injection and suction in micro- 

 scopic quantities is accurately controllable as the meniscus of the 

 mercury or oil in the pipette responds instantly to the pressure 

 of the leverage clamps. 



46 (1793) 



The effect of experimentally induced changes in consistency 

 on protoplasmic movement. 



By ROBERT CHAMBERS. 



[From the Department of Anatomy, Cornell University Medical 

 College, New York City.] 



Agitation by means of a micro-dissection needle tends to cause 

 the protoplasm of a living cell to pass from a more solid to a less 

 solid phase. 



In marine ova, where one can closely follow the solidifying of 

 the protoplasm just prior to cell division, mechanical agitation will 

 cause the protoplasm to revert to its original liquid state so that 

 the egg reverts to the shape of a sphere. If the egg so treated be 

 subsequently left undisturbed the solidifying process starts up 

 again with the result that the egg undergoes normal cleavage. 



In a previous communication 1 the writer has described the 

 structural relations of changes in protoplasmic consistency of the 

 Amceba to the formation of pseudopodia. The maintenance of 

 pseudopodia depends upon a relatively solid state of certain parts 

 of the Amceba. 



A resting Amceba, with numerous slender pseudopodia all over 

 its surface, is relatively solid. Upon mechanical agitation the 

 pseudopodia are retracted as the Amceba becomes more liquid. 

 Fresh pseudopodia in an agitated Amceba tend to be broad lobate 

 and, if the agitation be continued, all of the Amceba liquefies. 

 The entire body then becomes, as it were, a single pseudopodium 

 with a peripheral current of granules flowing away from its 

 anterior end and a central current flowing forward. An Amceba 

 in this extreme state does not change in position as the back flow 

 tends to equal the forward flow. Amcebce which are experimentally 



1 Chambers, Robert, Proc. Soc. Exp. Biol, and Med., 1920, xviii, 66. 



