COMPLEX COACERVATES AND PROTOPLASM 313 



number of the characteristics of intact protoplasm. This 

 phenomenon has been known ever since the time of Nageli*^ 

 and has since been studied in detail by W. Kuhne,"*^ W. 

 Pfeffer/* L. V. Heilbrunn/^ W. W. Lepeschkin*'^ and many 

 others with numerous plant and animal materials. ^'^ It may 

 be observed by causing the plasmolysis of plant cells even 

 without breaking the cell membrane (Fig. 29). When this 



Fig. 29. Domed plasmolysis of a cell of the 



epidermal scale of an onion. Vacuole stained 



with an anthocyanin (after Hefler). 



occurs, the bulk of the protoplasm becomes separated from 

 the cell wall but is not dissolved in the water which has 

 passed through it. It remains in the form of a sharply 

 demarcated mass.** Similarly, as we have already seen, 

 although artificial coacervates are drops of liqtiid containing 

 50 to 85 per cent of water, they do not mix with their equi- 

 librium liquids, which are almost colloid-free. 



We also find a close similarity between artificial coacervates 

 and protoplasm in regard to the phenomenon of vacuolisa- 

 tion. Under a number of conditions which cause a decrease 

 in the hydration of complex coacervates, clearly defined 

 vacuoles appear in them and these may take the form of 

 separate small bubbles or may coalesce to form a single 

 large vacuole. This phenomenon may be observed under 

 the action of chemical agents and also on changing the 

 temperature, under the influence of electric ctuTcnts and 

 so forth. When the agent which brought about the vaciio- 

 lisation is remo\'ed the phenomenon is reversed and the 

 coacervate rettirns to its original state. In a similar way 

 the same physical and chemical agencies can induce vacuolisa- 



