LIFE, ITS PHYSICAL BASIS AND SIMPLEST EXPRESSION .'J9 



into fine icy powder. But a temperature of -20 C. killed the 

 fish. According to L. J. Turner, the "Alaska mud-fish (Dallia), 

 was fed frozen to Esquimaux dogs. One of these thawing in 

 the stomach of the animal made its escape alive. Frogs lived 

 after being kept at a temperature of -28 C., centipedes, at 



FIG. 29. The piddock, Zirphnca crispata, a rock-boring mollusk. (Natural size, from 



life.) 



a temperature of -50 C., and certain snails endured a tempera- 

 ture of - 120 C. without dying. 



At the other extreme, instances are known of animals living 

 in water (hot springs or water gradually heated with the organ- 

 isms in it) of a temperature as high as 50 C. Experiments with 

 Amoebae show that these simplest animals contract and cease 

 active motion at 35 C., but are not killed until a temperature 

 of 40 to 50 C. is reached. 



Variations in pressure of the atmosphere also constitute 



