•2:\4 



Illation. A comparison of this pliciioiiiciioii wilh llic 

 t'oiitrac'tioii of iimscular 1 issue and of oIIrt forms of 

 eontrat'tile protoi)lasm 1)\ cold mii;lit not l)c out of 

 place. 



At first it appears somewhat surprising that the with- 

 drawal of water involved in this ])h('nomenon be at all 

 injurious and if it is injurious one would hardly expect 

 it to lead to death. 



2. l\apid Lijurious Aclhni. (a) In the ciliate Sff^utor 

 coendeus, Greeley (1901 and 11)U2) observed that while a 

 slow cooling- caused encystment or sporulation, a sudden 

 cooling was lethal. (The absence of ice formation within 

 the organisms themselves is evidently implied in the au- 

 thor's account.) In the last case, that is, after sudden 

 cooling, the animals were deformed, their pigments were 

 released and complete disorganization followed. In the 

 former case, when the rate of cooling was about 10 de- 

 grees per hour, the following sequence of phenomena 

 which is partly the same as that which often precedes 

 death was observed: 1. A cessation of body movements 

 and of ciliary motion; 2. The formation of vacuoles 

 which gradually increased in size; 3. A change in the 

 form of the cell which gradually became spherical; 4. 

 The separation of the nuclear material; 5. A transforma- 

 tion of the protoplasm into a granular mass; 6. The 

 throwing off of the ectosarc; 7. The transformation of 

 the cell into a cyst. The animal resumed its normal 

 activity upon an elevation of temperature. 



The fact that the final result of the action of low 

 temperature was death or encystment depending on the 

 velocity of cooling postulates that some similar mechan- 

 ism must underlie these tw^o processes. 



The reduction of the water content, Greeley suggests, 

 might be responsible for l)oth, cystogenic and lethal ac- 

 tion, as indicated by fnrtlicr cxpcrinicnts in which an 

 immersion of Sfoitor in a strongly hypertonic M/10 

 solution of sucrose, produced the same etfects as a 



