IV 



AND STRUCTURE OF THE CELL 



301 



Let us look a little more closely into the structure of this body, 

 and into the changes which it presently undergoes. 



Within its spherical outHne (Fig. 89 a), it contains an ''alveolar" 

 meshwork (often described, from its appearance in optical section, 

 as a "reticulum"), consisting of more sohd substances with more 

 fluid matter filling up the interalveolar spaces. This phenomenon, 

 familiar to the colloid chemist, is what he calls a "two-phase 

 system," one substance or "phase" forming a continuum through 

 which the other is dispersed; it is closely alhed to what we call in 



atr racHon - sphere 

 1 ,C€ntro3omes 



Fig. 89 A. 



Fig. 89 B. 



ordinary language a. froth ot'sl foam*, save that in these latter the 

 disperse phase is represented by air. It is a surface-tension pheno- 

 menon, due to the interaction of two intermixed fluids not very 

 different in density, as they strive to separate. Of precisely the 

 same kind (as Biitschli was the first to shew) are the minute alveolar 

 networks which are to be discerned in the cytoplasm of the cellf, 



* Froth and foam have been much studied of late years for technical reasons, 

 and other factors than surface-tension are foiind to be concerned in their existence 

 and their stability. See (int. al.) Freundlich's Capillarchemie, and various papers 

 by Sasaki, in Bull. Chem. Soc. of Japan, 1936-39. 



t Biitschli, Untersuchungen iiber mikroskopische Schdume und das Protoplasma, 

 1892; Untersuchungen uber Strukturen, etc., 1898; L. Rhumbler, Protoplasma als 

 physikalisches System, Ergehn. d. Physiologie, 1914; H. Giersberg, Plasmabau 

 der Amoben, im Hinblick auf die Wabentheorie, Arch. f. Entw. Mech. li, pp. 150-250, 

 1922; etc. 



