spirtx'lictcs, for cxniiiplc .-iikI those on the lissut'S of 

 higher plants, seems to indicnte. Px'sides there are I'Vi- 

 (lently otlier factors in the piolth-ni which haxc not yet 

 been analysed. 



\-. 'n!i:<H:v of diiatii r.v 1)i:iivi>i:ati()N 



After it had been observed that watei" eoiiios out of 

 the cells ilurin.n- fi-eezin<'- and i)asses into the intercellu- 

 lar sj^aces, the theory was proposed that death results 

 from the fact that congelation deprives the ])rotoi)lasni 

 of its moisture. Death by freezing- would then ])e ideu- 

 tical, in the last analxsis, with death by drou,i;lit. Sev- 

 eral eminent jilant pli> siolo,i;-ists towai'd the end of 

 the last and the be^innin^- of the i»i-esent century took 

 sides on this (juestion. We shall lu're sunnnarize, iu 

 ehrouolo,i;ical order, the most im])ortant works which 

 have conti-ibnted to the (leveloi)meiit of this theory. 



Sachs (18G0) is usually not considered an advocate 

 of the dehydration theory of death l)y freezing, though 

 some of his statements place him among the pioneers 

 who jtoinled onl tiie important alteration which I'e- 

 sults when water molecules are disengagi'd from a living 

 structure. He says that the molecules of water belong to 

 the structural organization of protoplasm and of the cell 

 walls, and are in a certain state of equilibrium wdtli the 

 otlier constituent molecules. By freezing and thawing, 

 the water molecules are i)ulled away from the structure 

 and a new^ state of equilibrium is established in w^hich the 

 other molecules have a stronger attraction for each other 

 than for water. This is ])recisely the mechanism which 

 several later investigatoi-s who hold the water with- 

 drawal theory assumed to explain injur>- and death by 

 freezing. 



MiilJcr-TJiinfidH (ISSd), who is ordinarily held as the 

 founder of this theory, ])ro])osed it in a I'ather hesitating 

 phraseology. He says that death is usually considered 

 as resulting fi'om a destrnction of the ordered arrange- 



