250 



TABLE 4 



ORtiAMSMs Which, in thk Wi:t Condition. Sikvivk Im.mkrsion in Liquid 

 Aiu, Pkovidki) Tiiky Akk Cooi.kd and Rkwakmi:!) Suddenly 



( VlTKlI l( ATION Fl{0( KDUKi; ) 



Organisms 



Conditions of Exposure 



Myxamoebae 



Moss Leaves (with full 



water content) 

 Onion Epidermis 



Fros Spermatozoa 



Frog Muscle Fibers 



Investigators 



Suspended in films of, Gehenio and Luyet, 

 water in a thin wire 1939 



loop 



Previously plasmolysed 

 in NaCl solution 



Previously plasmolysed 

 in sucrose solution 



(unpublished) 

 Luyet and Gehenio, 



1938 

 Luyet andThoennes, 



1938a 

 Luyet and Hodapp, 



1938 

 Luyet andThoennes, 



1938b 



peratures"). However, the absence of experimental evi- 

 dence is not an argument against the possibility of the 

 theory. 



Another reason which might be suggested for the re- 

 sistance to extreme cold of the organisms of the second 

 group is that their small size provides them with such a 

 large surface area, in comparison with their volume, 

 that they can lose water by exosmosis in the short time 

 during which their culture medium freezes. The cells, 

 being then dehydrated as a result of the congelation of 

 the water around them, would naturally become resis- 

 tant. An objection to this interpretation is that osmosis 

 is known to be a comparatively slow process which would 

 hardly account for the dehydration of even a small speck 

 of protoplasm during the few seconds necessary for freez- 

 ing a small drop of culture medium in li(|uid air. 



Luyet and Gehenio (19.'^9, p. 123) proposed a third ex- 

 planation for the prevention of congelation in microor- 

 ganisms which survive the lowest temperatures in the 

 vegetative state. According to Luyet ( VXW)) water solu- 

 tions of substances which have a hii>h mok'cnlar weig-ht 



