202 



known llial, in llic antninn, the snails lose a considerable 

 amoiinl of water before enteriii*;' into the dormant state, 

 the increased tendency to suIk'ooI siioiild, jx'rhaps, l)e 

 atti-il)iited to the concentration of body fluids. 



SUMMARY 



1. Some fundamental principles on the nature of sub- 

 cooling- and the mechanism of crystallization in a subeooled 

 liquid are outlined. 



2. In an analysis of the sulx'ooling curve, two problems 

 are discussed: a. The maximal temperature reached by 

 the ascending curve; b. The quantity of heat liberated 

 as calculated by the method of the freezing-curve-area. 



3. The factors inducing or preventing cystallization, as 

 studied by the physicists and the biologists, are reviewed ; 

 the following topics are considered: a. Temperature, spe- 

 cific response to temperature, destruction of centers by 

 previous warming, duration of previous warming; b. In- 

 oculation, inoculation by isomorphous crystals and other 

 bodies, inoculation of tissues through cell membranes 

 mostly by surface moisture ; c. Time factor, maintenance 

 of the subeooled state for long periods; d. ^lechanical dis- 

 turbance, its frequent inefficacy, its undeniable efficacy in 

 other cases, the magnitude of the disturbance required, the 

 specific sensitivity to mechanical disturbance; e. Capillar- 

 ity, the inconsistency of the experimental data; f. Impuri- 

 ties, air, oil droplets, colloidal particles. 



