PROTOPLASM OF PROTOZOA 55 



vacuolated protoplasm. Immersion in NaCl or KCl dissolves the vacuolar 

 membranes, with a dissolution of the intervacuolar protoplasm. Im- 

 mersion in strong concentrations of CaCL causes coagulation of the 

 protoplasm; in weak solutions the coagulation may be local, and the 

 living remnant rids itself of the coagulated regions. After immersion 

 in strong concentrations of MgCL the protoplasm coagulates into a 

 flabby mass; in weaker solutions localized regions rupture. Injections 

 result in similar but more localized effects, except in the case of MgClg. 



THE EFFECTS OF ACIDS AND ALKALIES 



There seem to be no general agreement on the effects of acids upon 

 protozoan protoplasm. Some authors report that they cause an increase 

 in viscosity, while others find that they produce a decrease in viscosity 

 of the protoplasm. 



Jacobs (1922), by bubbling CO, through the culture medium con- 

 taining Paramecium and Colpidium, observed that short exposure of 

 these organisms to the CO, caused a decrease in the viscosity of the proto- 

 plasm, while longer exposures increased it. Brinley (1928) found that 

 CO2 caused gelation of the ectoplasm and solation of the endoplasm of 

 A. proteus. Reznikoff and Chambers (1927), after injecting bubbles of 

 CO2 into A. dubia, observed that it produced a decrease in the viscosity 

 of the protoplasm and that the animal was not irreversibly injured un- 

 less the CO2 destroyed the cell membrane. Hydrochloric acid has been 

 observed to produce an increase in the viscosity of the protoplasm of 

 Amoeba (Chambers, 1921; Edwards, 1923; Brinley, 1928). Heilbrunn 

 (1937) finds that acids cause an increase in viscosity of both the plasma- 

 sol and plasmagel of Amoeba. 



Chambers (1921) reports that basic dyes, which contain a relatively 

 strong acid radical, jelly the protoplasm of Amoeba, whereas acid dyes, 

 with a strong basic radical, liquefy it. 



The action of alkalies has been reported to decrease the viscosity of 

 A. proteus (Chambers, 1921; Edwards, 1923; Brinley, 1928). How- 

 ever, Heilbrunn (1937) reports that alkalies increase the viscosity of 

 the plasmasol and decrease the viscosity of the plasmagel in Amoeba. 



THE EFFECT OF TEMPERATURE 



As pointed out by Brues (1927), the Protozoa are among the most 

 resistant of all animals to high temperatures; they have been found liv- 



