THe INFLUENCE OF Low TEMPERATURE ON Sort BAactTERIA 1051 
of thaw, except in a few specific cases. They believed that death was 
due to the rapid withdrawal of water from the ceil to form the ice crystals 
in the intercellular spaces during the process of freezing, and that only 
when freezing took place very rapidly were ice crystals formed within 
the cell. Unfavorable conditions appear in general to reduce the power 
of resistance to cold, and a deficiency or excess of water or plant food 
would act in the same way. 
Klemm (1895) noted that the visible changes and deformations pro- 
duced in the protoplasm were due to sudden changes in temperature, and 
were not present when the cells were subjected to gradual changes. 
D’Arsonval (1901) noted that yeasts and bacteria did not lose their 
vital properties when placed in liquid air for weeks. He thinks the 
fluid in the cell is probably. not solidified if the cell is not ruptured, owing 
to the enormous osmotic pressure in those small organisms, for if their 
osmotic tension is lowered by placing them in a solution of sodium chloride, 
potassium chloride, or glycerin, they are readily killed. He suggests the 
possibility of determining the osmotic pressure of any given cell by the 
temperature at which its vitality is destroyed. 
Matruchot and Molliard (1901) subjected plants to freezing, to drying, 
and to the action of solutions of high osmotic concentration., They 
observed a marked parallelism between the action of freezing and that of 
drying, and they concur with Molisch in that the death of the cell is due 
to a rapid drying-out of the tissues. 
Mez (1905) noted, in his studies of the effect of supercooling on plant 
tissue, that where the ice formation began at once on reaching the freez- 
ing point the killing was not so great as where there was supercooling, 
and the formation of ice crystals took place rapidly. He thinks that 
when a temperature of —6° C. is reached, all solutions will crystallize 
out. The heat liberated by the crystallizing of the solutions and the 
formation of ice, will, after the cells are insulated by the ice mass, aid in 
keeping the temperature of the cell above that of the surrounding material. 
Mez holds that death is due to the direct effect of the cold. 
Gorke (1907) noted that when the cell sap was frozen, certain proteids 
were precipitated, and that those plants that are most easily killed by 
freezing have their proteids precipitated at the highest temperatures. 
By using solutions of albumin to which had been added zine sulfate, he 
was able to show that the concentration of the salts had a marked effect 
