DO 



Weigmaim (15).")()) stiulied dcatli Icnipcratures in stickle- 

 backs cooled slowly in water. Ho inserted a thormoconplc 

 into the body of a few specimens and showed that wiien 

 the temperatnre of the water was lowered, that of the 

 animal followed closely (how closely depends, of course, 

 on the cooling velocity and the size of the animal). As to 

 the death tem})eratnre, he observed that all the fishes died 

 when their body became surrounded with ice but before 

 being actually caught in ice. The maximal resistance 

 registered was 20 minutes at bath temperatures of - 2.5° 

 to -3.2°, which would give for the lethal body tempera- 

 ture, -2° to -3°. The author remarks that a velocity of 

 cooling varying from 0.02° to 0.6° per minute had no influ- 

 ence on death or survival. 



Schmidt, Platonov and Person (1936) subjected to cold 

 carps maintained in air, determining their internal tem- 

 perature with thermocouples. They found that these 

 fishes could be revived if their body temperature, mea- 

 sured at a depth of 1.5 to 2.5 cm, from the surface of the 

 skin, did not fall below -0.72° to -0.92°. In the outer 

 surface layers of the body, - 3.33° was recorded. In an- 

 other series of experiments, the same authors revived 

 hJeaks and sticMehacks subcooled to -3.06° (body tem- 

 perature). None of the fishes experimented upon ever 

 survived a congelation of its body. 



Luyet (1938), in an attempt to test a theory according 

 to which a rapid freezing would cause the formation of 

 smaller crystals less injurious to the cells, studied the 

 effects of a sudden immersion of gold fishes in liquid air. 

 He could never obtain any sign of recovery if the immer- 

 sion had lasted more than 15 seconds (for fishes 40 mm. 

 in length, not counting tlie caudal fin). However, after 

 that time, the fishes were not frozen throughout, it requir- 

 ing about 35 seconds for them to become breakable. Im- 

 mersions of 1 to 15 seconds caused gradually increasing 

 injuries, corresponding to the gradually increasing thick- 

 ness of body wall congealed. The author, who reports 

 that a juggler had as a regular item in his program the 



