225 



ficatioii occurs in a definite range of temperatures and the 

 devitrifying mass acquires a tufty structure. When one 

 passes to lower concentrations, the ranges of devitrifica- 

 tion temperatures move suddenly higher and the devitrify- 

 ing material appears as a transparent mass of amber color 

 which gradually darkens to complete opacity. The beha- 

 vior of these three groups of concentrations is attributed 

 to three modes of binding of water. 9. Within the range 

 of concentrations of the last group mentioned, the devitri- 

 fication temperatures decrease slightly with increasing- 

 concentration, a phenomenon perhaps comparable to the 

 depression of the freezing point of solutions. 10. By a 

 rapid warming (immersion in warm water), one can avoid 

 devitrification (crystallization) and pass directly from the 

 vitreous to the liquid state; we call this change of state 

 "vitrofusion." 



11. Assuming as a working hypothesis that it is usually 

 the formation of ice which kills protoplasm at low tem- 

 peratures, we studied the vitality of organisms subjected 

 to the vitrification and vitrofusion procedure. 12. The 

 protozoa : eugiena, Paramecium and amoeba did not sur- 

 vive the treatment, but w^e have no guarantee that they 

 have not been frozen. Some myxamoebae survived. 13. 

 Some frog spermatozoa resumed their motility after solidi- 

 fication in liquid air ; rat spermatozoa never did. 14. The 

 cells of the epidermis of the onion were capable of plasmo- 

 lysis after vitrification and vitrofusion. 15. Plant leaves 

 could be vitrified, but we are not sure that their vitrofusion 

 has succeeded. In general, they appeared severely in- 

 jured after being brought back to room temperature. 16. 

 Moss leaves have given results in perfect accord with the 

 anticipations relative to the innocuousness of vitrification 

 and the fatal action of freezing. The cells were always 

 alive after rapid cooling and rapid warming and always 

 dead after slow treatment. 17. Frog muscle fibers re- 

 sponded to electric stimuli after the vitrification and vitro- 

 fusion procedure. 



