Freezing Injury of Seed Corn 
23 
material damage after thawing whether the latter process 
takes place slowly or suddenly. 
Coming back again to the belief held by Sachs, it is stated 
by Adams (1905) that during the freezing process water is 
drawn from the cells and solidified in the intercellular spaces, 
and that if freezing has not gone too far, and if thawing be 
gradual, the ice melts and is absorbed again by the cells and 
no injury results. In discussing the effect of freezing on culti- 
vated plants, Galloway (1895) makes a similar statement. 
Brown and Escombe (1897-1898) while trying to determine the 
influence of very low temperatures on the germinative power of 
seeds, express the opinion that the vitality of the seeds was 
injured more by rapid thawing than by gradual thawing. 
DESICCATION OF THE PROTOPLASM 
Probably the most generally accepted theory of the cause 
of death from freezing has been, that death results from desic- 
cation of the protoplasm when water is drawn from the cells 
into the intercellular spaces in the process of ice formation. It 
was early discovered that when plant tissues freeze, water is 
drawn from the cells and ice crystals are formed in the inter- 
cellular spaces. Geoppert (1830) and Sachs (I860) both 
observed these phenomena but reached rather different con- 
clusions as to the real cause of death. Geoppert thought that 
death resulted as a direct effect of freezing and that death 
occurred while the tissues were still in a frozen condition; while 
Sachs thought that death occurred during the thawing process. 
That water is withdrawn from the cells during the process of 
freezing and that ice crystals are usually formed in the inter- 
cellular spaces, and only rarely within the cells, was again 
declared by Muller-Thurgau (1886) and also by Molisch (1897) ; 
the latter observing the movement of water and the formation 
of ice crystals in plant tissues under the microscope. Both of 
these men were of the opinion that death from freezing is due 
to the withdrawal of water from the cells, and that it is essen- 
tially the same thing as death from desiccation. Miiller- 
Thurgau went so far with his work as to determine the amount of 
water drawn from cells by freezing. For apple he found that at 
a temperature —13 degrees C., 63.7 per cent had been lost, and 
at — 15.2 degrees C.. 79.2 per cent of the water had passed from 
the cells. 
In regard to the effect which the removal of water may 
have upon the cell contents. TTiegand (1906) thinks it is proba- 
ble that death from freezing is caused by drying out of the proto- 
