STRUCTURE OF PROTOPLASM OF PARAMOZCIUM. 



FIG. 6. Liquefied protoplasm 

 of Paranict'cium under ^ oil -im- 

 mersion. Formed by an exposure 

 of two hours to w/32O Na 2 SO 4 . 



are discernible only under high magnifications. At the same 

 time a rapid absorption of water takes place, and the particles 

 become widely separated in the now exceedingly fluid cell sap. 

 We thus have a means of distinguishing between liquefaction by 

 chemical and osmotic means. As has been described above, 

 the central feature of the process of 

 chemical liquefaction is a splitting 

 up of the protoplasmic particles and 

 consequent imbibition of water 

 through this increase in the absorb- 

 ing surface (see Fig. 6). In the 

 process of osmotic liquefaction, how- 

 ever, the size of protoplasmic par- 

 ticles remains unchanged, and water 

 enters the protoplasm solely because 

 of the osmotic relations between 

 the cell-sap and the surrounding liquid. These two processes 

 can be distinguished microscopically as indicated even under 

 a low magnification, for paramcecia that are liquefied osmotically 

 never lose their granular appearance, while those liquefied chem- 

 ically become markedly transparent. 



That in these phenomena we are dealing also with variations 

 in the surface tension relations of the protoplasm is apparent 

 from the change of form which occurs during coagulation and 

 liquefaction. The surface tension force is neutralized either by 

 an increase in temperature or by giving all the protoplasmic 

 particles a like charge which tends to make them mutually re- 

 pellent, and thus introduces a disrupting force. Hence, if we de- 

 stroy the electrical charge, we not only allow the protoplasmic 

 particles to fuse, but we increase the surface tension. Thus, dur- 

 ing coagulation, the cell tends to assume a spherical form which 

 is characteristic of all resting cells. The opposite is true during 

 liquefaction. The disrupting force is still further increased by 

 the introduction of a charge of the same sign as that carried by 

 the protoplasmic particles, and the cell assumes an irregular 

 form. The most powerful anions used, the phosphate and cit- 

 rate, bring about this disruption of the cell with almost explosive 

 violence, so that the cell membrane bursts and the protoplasmic 



