INFLUENCE OF GLANDULAR K.\TRA< ' I >-. 25 



Ehrmann (8) set this normal average as twelve for Paramecium. 

 Hance (u) found that with multiple vacuoles there is an increase 

 in pulse frequency toward the posterior end. The observations 

 reported in this paper will show however that this may occur 

 also in normal individuals. Moreover, the reverse is frequently 

 true, that the anterior vacuole or vacuoles may pulsate more 

 rapidly than the posterior. Rossbach (24) experimenting with 

 temperature changes, gases, chemical solutions and electricity 

 found that rate of contraction increased with rise in temperature 

 and with most chemical reagents. Dilation with retardation 

 was produced by neutral substances and alkaloids, and no 

 effect whatever was noticeable with currents of oxygen or of 

 electricity. Korentschewsky (17) confirmed this retarding 

 effect of alkaloids. 



Degen (6) published an exhaustive treatise on the physiology 

 of the vacuole. Continuing the temperature experiments of 

 Rossbach, he established a maximum and minimum for the 

 organism. Around zero degrees he found a great variation in 

 pulse frequency, but a generally slow contraction with dilation 

 of the vacuole. At about three, Centigrade, dilation ceased and 

 the pulse frequency became more and more rapid until the 

 animal plasmolysed at about thirty-four degrees. Doflein (7) 

 gave the optimum temperature as thirty to thirty-five degrees 

 for Paramecium. In contrast to Rossbach.'s observations (24) 

 Degen found that a current of oxygen produced a pulse quickening 

 to compensate for the increased output of carbon dioxide pro- 

 duced by the accelerated metabolism. Hydrogen, however, 

 retarded the pulse, dilated the vacuole and caused dissolution in 

 four or five hours. When subjected to carbonic acid gas the 

 vacuole dilated with an increase in pulse frequency and dissolu- 

 tion occurred in two hours. Minchin (21) observed that carbon 

 dioxide diminished the frequency. This seeming contradiction 

 may be due to the specific resistance of the organism in media 

 saturated with the gas. Jacobs (13) believes that the organisms 

 in such environment develop a remarkable resistance to other 

 chemical factors. That pulse frequency often may be attribut- 

 able to the concentration of the surrounding medium was shown 

 by Degen in the effects of chemical solutions of varying strength. 



