l('iHl»('r;i1iii-c williiii ihc dyiiii;' nialcrial; 5. Tlic tiniL' of 

 action of this latter tcinpciat iiro ; (5. Tlie rate of cooling 

 and, if the material was thawed, tiie i-ate of warminji': 7. 

 The presence or absence of ice in the tissne, in the cells or 

 in the ])rotoplasm; S. The state and the conditions of the 

 malei-ial, before and during' coolin.n', snch as, its acclimati- 

 zation to low temi)t'ratni-es, its water content, its thermic 

 insnlation, etc. 



Inmost of tile older works on death by low temperature, 

 only the tirst two of these factors, that is, the typo of 

 organism and the external temperature, are recorded. 

 This literature, therefore, does not bring much substantial 

 information on the point at issue in the present work, 

 and we shall mention only some of the most outstanding 

 results obtained by the older investigators. Those papers 

 of later date which contain enough of the data mentioned 

 in tlie previous paragraph to be significant will be sum- 

 marized and some of them will be discussed briefly. 



Immersion in liquid gases has been the usual method of 

 subjecting living matter to extreme cold. The liquefac- 

 tion temperatures of most of the gases used are given in 

 the following list and will not be indicated for each par- 

 ticular case in the text. 



Absolute Zero -273° C. 



Temperature of liquefaction of Helium - 269° C. 



Temperature of liquefaction of Hydrogen - 253° C. 



Temperature of liquefaction of Nitrogen -196° C. 



Temperature of liquefaction of Air - 192° 0. 



Temperature of liquefaction of Oxygen - 183° C. 



Temperature of sublimation of Carbon di- 

 oxide - 78.5° C. 



Temperature of liquefaction of Sulphur di- 

 oxide - 73° C. 



Some conditions of the experiments, which follow as 

 natural consequences from other fully described condi- 



