iiiotii>ii, one oaiiiiot kill il. it sih'ius. by loworinu" its tom- 

 poraturo oven to near tlio absolute y.ovo, that is, by iu>arly 

 stoppiiiii" its moleeular motion. In the last analysis, how 

 ever, the nieehanisni o\' action of hi^h and that o^ low 

 temperature mi^ht not be so ditVerent as it appears. The 

 theories ot" injury by hiiih temperature let'. Belehradek, 

 llK>r)) attribute death to some indireet et'feet of heat, sueh 

 as protoplasmic coaiiulation. tlu' destruction oi' some en- 

 zyme, the \apori/,atit>n o[' lipoids, etc., in the same way as 

 death by cold is attributed to some indirect elVect of 

 temperature such as the freeziuii' ol' water. It seems 

 then that it is not temperature itself, hiiili or low, in (»ther 

 words, it is not the ra])id or the slow molecular m(»tion, 

 which disturbs the structural architecture o\' livinu' mat- 

 ter, but the indirect chanues caused by certain particular 

 rates of molecular motion. 



Water api)ears to pla>' a role o\' fundamental impor- 

 tance not only, as is well known, in the fi(>ictii>ns o( liviuii* 

 nuitter at the temperatures of active life but also in the 

 sfntctiirt' o^ the livinu' units, as is shown by the destruc- 

 Xiou o[' proto]ilasm when the molecules of water arc torn 

 away, in the process of devitrilication, for example. 



Adams 1^1905) points out that at extremely low tem- 

 peratures not only water should be soliditied in proto- 

 plasm but also carbon ilioxide. and that oxyuen and nitro- 

 jjon should litpiefy or soliilify tO(>. The se]iaratiim of 

 these substances from protoplasm and the mechanical 

 injury possible as a result of the reduced lucssure caused 

 by these changes of state, might be expected t(^ cause 

 damage. However, the fact seems to be that the sep- 

 aration of these substances is hannless, while the separa- 

 tion of water is highly injurious. The importance of 

 the crystallization of water in death by low tempera- 

 ture is emphasized in the diagram above where one of 

 the main lethal zones is at the freezing point of water. 



The observatitui that living matter can stay for a long 

 time near the absolute zero without showinu- anv measnr- 



