161 



cooling velocity of 10 to 14 degrees per minute used by 

 Voigtlander. This contirms Maximov's view that Voigt- 

 lander's curves present a double freezing point but no 

 eutectic. 



Moran (1935), who defines the eutectic point as "the tem- 

 perature at which all free water is frozen," determined this 

 temperature in a concentrated filtrate of muscle juice. For 

 that purpose he measured the electric resistance of the 

 material when the temperature was lowered, there being 

 quite a definite change in resistance at the eutectic. He 

 obtained the value -37.5°, which he considers as the 

 ' ' eutectic temperature of muscle. ' ' 



One must confess that there is little experimental evi- 

 dence for the existence of a eutectic freezing in tissues, 

 despite the fact that' a considerable portion of plant juices 

 and body fluids are true solutions, from which one would 

 expect a eutectic freezing. The problem of the eutectic, 

 therefore, remains almost entirely to be investigated. 



Q u a n t i t y o f I c e F o r m e d. In the study of death 

 by low temperatures, biologists have attempted to find, 

 from an analysis of the freezing curves, the proportion of 

 water frozen at a given temperature, in order to determine 

 if death by freezing is conditioned essentially by the quan- 

 tity of water withdrawn from protoplasm. In doing so, 

 they have generally observed that the descending portion 

 of the freezing curve which follows the horizontal plateau 

 is maintained for a long time at a level higher than one 

 should expect if all the water were frozen. 



Miiller-Thurgau (1886), by recording the time necessary 

 for the freezing curve to fall from the freezing point to 

 - 1°, from - 1° to - 2°, etc., concluded that, in a tissue, the 

 amount of ice formed during the first part of the freezing 

 period is considerably greater than that formed later ; but 

 there was still some crystallization when the curve had 

 dropped several degrees below the freezing point. This 

 Avas confirmed by the observation that the ice masses 

 formed in the intercellulars of a tissue exposed for several 

 hours to -10° were larger than those formed after an 

 exposure to -4°. 



