high enough, the cells will either disintegrate completely 

 or coagulate, v/ith the result that the cell boundary can no 

 longer be seen. The ttmoerature at which the spherical 

 shape was assumed, and the temperature at which death 

 occurred are recorded below. 



Lxp. 



Spherical shape assumed 



Death 



Nucleated Non-nucleated 



•^r C. 



50 



40° • 

 40". 2 



50 C. 



a 



50-^ 



52'' 

 48' 



50 U 



The effect of gradual cooling was not so easily deter- 

 mined. When the temperature of the fluid was lowered great- 

 ly and even super-cooled, there was no injury provided crys- 

 tallization did not take place. '.'men the solution crys- 

 tallised, however, as the result of adding a small crystal 

 of ice, the amebas were injured mechanically, and disinte- 

 grated as soon as the solution nelted. 



out the effect of cooling could be shown in a some- 

 what different manner. The nucleated and non-nucleated 

 parts of an ameba were slowly warmed tn 44° C, and then 

 cooled in ten minutes to 22'^ C . Two minutes later, both 

 fragments disintegrated at the same time: the result of 



(52) 



