276 



The lirst of those processes, namely the eessalioii of 

 proto])hisniic streainiiiji:, does not seem to l^e satisfac- 

 torily exi)huned by dehydration. Protophisniic stream- 

 ing- has been observed to l)econie sh)wer and to stop 

 under the action of h)W tenii)ei-ature ^vitllont ice for- 

 mation, that is, without (h'h>(li'ation to any noticeable 

 extent. 



Ill an attem))t to analyse the mechanism itself of death 

 ])y dehydration, Matruchot and Molliard, following some 

 views previously held by Dastre, distin,i>uish 3 sorts of 

 water in living matter: 1. External water, that is, the wa- 

 ter of the cell sap, which does not enter into the make-up 

 of living protoplasm; 2. Iiiterpos<(1 water, the molecules 

 of which move freely in the capillary spaces between the 

 micelles, that is, within the meshes which constitute 

 protoplasm; 3. Constituent water which is either a part 

 of the protoplasmic molecules or is attached to them by 

 adhesion forces. The withdraw^al of external Avater 

 would be harmless and would leave a still liquid proto- 

 plasm. The withdrawal of interposed water would not 

 be usually lethal and Avould result in the production of 

 that more solid sort of protoplasm found in seeds or 

 spores. As to the constituent water, its separation from 

 protoplasm would induce death. 



Pfeffer (IdO'i) formulated several objections to the wa- 

 ter withdrawal theory. The essential points in his ob- 

 jections are the following: 1. There is a contradiction 

 between the fact that desiccation of a plant increases its 

 resistance to cold and the theory that desiccation by cold 

 causes death. 2. More water can be removed without in- 

 jury by transpiration and by plasmolysis than by freez- 

 ing. 3. Death by cold is in several cases independent of 

 the water content: some plants survive cold when they 

 are in the turgescent state while others, like seeds, sur- 

 vive in the dry state. 4. To account for the death of 

 some plants at temperatures far below the freezing 

 point one would have to assume that some moisture does 

 not freeze until these low temperatures are reached, an 



