14 A. W. GREELEY. 



coagulating solutions, in dilutions which are roughly proportional 

 to their valence. 



The univalent salts have a comparatively weak effect upon the 

 protoplasm, and relatively high concentrations are necessary 

 before we can be sure that the liquefaction is due to chemical 

 and not osmotic means. In solutions of the bases, bivalent and 

 trivalent salts, however, the effects are unmistakable, and are ex- 

 actly the reverse of those initiated by the coagulating solutions. 

 Within a very few minutes after immersion in the solution lique- 

 faction first becomes discernible as a clearing of the protoplasm. 

 This process proceeds until the protoplasm loses its character- 

 istically granular appearance, and becomes semi-transparent. At 



FIG. 5. A Paramaecium in mj^2O Na. 2 SO 4 , showirg a typical liquefaction 



of the protoplasm. 



the same time the cell membrane becomes greatly swollen through 

 the absorption of water, which frequently gives the protoplasm a 

 vacuolated appearance, and gives rise to droplets which cling to 

 the protoplasm underneath the cell wall. The result is an irregu- 

 lar watery mass of protoplasm from which the solid elements 

 have, to a superficial examination, completely disappeared (see 

 Fig. 5). In the solutions of trivalent salts these changes occur 

 with such violence that the cell membrane is disrupted, and the 

 disintegrated protoplasm becomes scattered throughout the solu- 

 tion. Thus the liquefying anion has the same effect upon the 

 protoplasm as a slight increase in temperature. 



If, as in the case of the process of coagulation, these micro- 

 scopic changes be studied under a one-twelfth inch oil-immersion, 

 it will be at once seen that a change in the physical state of the 

 protoplasmic particles is responsible for these profound structural 

 modifications. The particles apparently continue to divide as 

 the process goes on, until their size becomes so small that they 



