PROTOPLASM OF PROTOZOA 53 



certain marine amoebae to be comparable to that of vaseline, i.e., over 

 1,000 times that of water. 



Fetter (1926), using the same method as Heilbrunn, found the 

 absolute viscosity of Paramecium to be 8,027 to 8,726 times that of 

 water. Hyman (1917) has found that the heliozoon Actinosphaerium 

 eichhornii can be cut into pieces as if it were solid. In addition to the 

 viscosity and the changes in viscosity of the protoplasm which may take 

 place within organisms under "normal" conditions, certain experi- 

 mental conditions, such as abnormal salt concentration, acids, and 

 alkalies, abnormally high or low temperature, mechanical agitation, 

 changes in hydrogen-ion concentration, anesthetics and narcotics, radia- 

 tion, sound waves, and so forth, may cause marked changes in the 

 viscosity of the protoplasm. 



The effect of various agents (chemical, mechanical, electrical, and 

 so forth) upon the viscosity of protozoan protoplasm has been deter- 

 mined by studying their effect upon locomotion, Brownian movement, 

 body form, pseudopod formation, rate of action of the contractile 

 vacuole, as well as by centrifuging and by the microscopic appearance 

 of the cytoplasm. 



THE EFFECTS OF WATER 



Since the principle solvent of protoplasm is water, any condition 

 which tends to increase or decrease the water content of the organism 

 also tends to change the viscosity or consistency of its protoplasm. Thus 

 hypertonic solutions and desiccation usually cause the cells to shrink, 

 this being accompanied by an increase in the viscosity of their proto- 

 plasm; a hypotonic solution or the injection of water directly into the 

 organism tends to induce a swelling, accompanied by a decrease in the 

 viscosity of the protoplasm (see Pantin, 1923) . 



THE EFFECTS OF SALTS 



The effects of salts on the consistency of certain Protozoa, particularly 

 Amoeba, have been rather extensively studied. Giersberg (1922), Ed- 

 wards (1923), Chambers and Reznikoff (1926), Reznikoff and Cham- 

 bers (1927), Pantin (1926a, 1926b), Brinley (1928), Heilbrunn and 

 Daugherty (1931, 1932, 1933, 1934), Thornton (1932, 1935), Pitts 

 and Mast (1934), Butts (1935), and others have studied the action 



