The Effect of Temperature upon the Non-Nucleated Cell. 



In the experiments hitherto reported, a fairly con- 

 stant temperature of 20' C. had been maintained. An attempt 

 Wiis now made to determine the effect of temperature upon 

 the nucleated and non-nucleated cells, with the hope of 

 discovering a possible difference in the rate at which 

 chemical changes were occurring in the two cells. Two 

 methods of investigation suggest themselves: 



(1) The temperature of the medium is gradually raised 

 until death occurs. 



(2) The organisms are kept at a rather high temperature, 

 and observed until death occurs. 



Both of these methods were used in the order named. 



In the first method, amebas were placed upon a 



Pfeiffer warming stage, thru which water of any desired 



temperature could be passed. After dividing the ameba 



into two e-iUal parts, the temperature of the warming stage 



was raised at the rate of about one degree Centigrade per 



minute. The rate at which the temperature is raised is 



of importance, for by raising the temperature rapidly, the 



organisms may be killed at a comparatively low temperature. 



As the temperature rises, the at^ebas soon withdraw all of 



their pseudopods and assume a spherical shape. This does 



not, however, indicate the death of the organism., for if 



at this point the temperature is slowly lowered to 20 C, 



the animals will, in a few hours, send out pseudopods and 



resume normal movement. If the temperature is raised 



(51) 



