V26 



llicfinal ui'adiciil Iliroiiuli llic iiialci'ial, llicx' scjtai'ali'd llu' 

 latlcr from the ('ooliiii'' hath hy media ol" \-ari()iis lliickness 

 and of various licat coiKhiclivil y, sucii as mercury or 

 ])araf1iii oil. Their liiidiiii^s can he summarized as foUows: 

 1. The ohserxatious of ])i-evious investigators, according to 

 which dead tissues do not present a douhle freezing point, 

 were verified in two series of experiments : one on living 

 tissues in which IV.] out of 68 specimens showed the double 

 freeziuii' poiiil, and one on dead tissues (killed by previous 

 freezing) in which none of the 44 specimens experimented 

 upon presented the double freezing point. 2. The obser- 

 vations to the effect that soaking the tissues induces double 

 freezing, while di'ying prevents it, were also confirmed; 

 the per cent of cases })i-esenting a double freezing increased 

 from 49 to 90 by a soaking of the tissue in water for 30 

 minutes or more and decreased to by a drying in the air 

 for 3 hours or more. 3. The first freezing point in normal 

 living tissues varied from - 1.2° to - 2.0°, the second from 

 - 1.45° to - 2.74° ; that of dead tissue was higher than both 

 and varied from -0.5° to -0.75°. 4. The first freezing 

 point was raised by soaking; in some soaked tissues it 

 reached -0.05°. The second was not influenced by the 

 imbibed water. 5. When congelation was stopped at the 

 passage from the first freezing point to the second, the 

 tissue was uninjured and the first freezing point could be 

 obtained repeatedly in subsequent experiments. 6. The 

 position of the first freezing point was not affected by a 

 change in the cooling velocity, while that of the second 

 moved from - 1.45° to - 2.3° for velocities varying from 2.5 

 to 5.1 degrees per minute. 



In the light of these findings the authors discuss the fol- 

 lowing four theories on the doubling of the freezing point 

 in living tissues : 



1. The "Wound-Sa])" theory, proposed by Maximov, 

 according to whicli, as said above, the two i)oints would 

 represent, res})ectively, the freezing of the sap extruded 

 from the cells through the wound caused by the insertion 

 of the thermocouple and the freezing of tlie water of the 



