314 ORGANISATION IN SPACE AND TIME 



tion in the protoplasm of very diverse animal and vegetable 

 objects.*^ It is interesting that this vacuolisation occurs not 

 only in the cytoplasm, but also in the nucleus, nucleolus, 

 chondriosomes and other organelles of the cell. This has led 

 a nimiber of authors to state that these organelles are of the 

 nature of coacervates/" 



The great similarity between artificial coacervates and 

 protoplasm has been revealed by concurrent studies of such 

 properties as their viscosity, their behaviour with neutral 

 salts, changes of pH and temperature, their behaviour in an 

 electric field and so forth. In introducing an extensive 

 account of his findings concerning the problem A. S. 

 Troshin'^^ writes as follows: 



Thus a number of features which are characteristic of the 

 physico-chemical properties of coacervates seem also to be char- 

 acteristic of protoplasm. The view of many investigators, that 

 the protoplasm of living cells consists of a system of complex 

 coacervates, is thus fully confirmed by experiment. 



The following two characteristic properties of complex 

 coacervates are specially important in relation to the argu- 

 ment which follows: (1) their tendency to form structures ; 

 (2) their ability to adsorb selectively substances from the 

 surrounding equilibrium liquid. It has been indicated above 

 that on the coacervation of organic substances of high mole- 

 cular weight there is formed a disperse system of coacervate 

 drops with highly developed surfaces and definite internal 

 structures. If the stability of the drops of coacervates of 

 simple liquids is determined by the surface tension of the 

 boundary layer then that of coacervates of proteins and other 

 substances of high molecular weight is determined by far 

 more complicated circumstances. In this case too the surface 

 tension (which amounts to 0-2-2 dyne /cm. for coacervates) 

 will naturally play some part, but will not be decisive. The 

 work of P. Rebinder and his schooP^ has shown that the 

 stability of disperse systems resembling emulsions depends to 

 a considerable extent on the stabilising effect of the adsorbed 

 layers at the surface which separates the droplet from the 

 continuous phase. This stabilising effect is especially marked 

 when the adsorbed layer with its associated solvent has a 



