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INORGANIC SALTS TO MONILIA SITOPHILA 287 
mycelium to take up sufficient water. By lowering the vapor 
tension of the medium it also increases the rate at which water is 
lost by the fungus. If instead of adding the salt to the medium it 
is dissolved in a small amount of water and suspended above a 
young culture the strong solution takes up water from the air. 
In this case the salt does not retard the rate at which water is 
taken up by the mycelium but does increase the rate at which 
water is given off. It is very interesting to see that when the salt 
is suspended above the growing culture it causes a decrease in the 
rate of growth which is similar to that to be observed when it is 
added directly to the medium. There can be little doubt that in 
media containing toxic concentrations of potassium chloride, the 
retardation in growth is largely the result of the inability of the 
fungus to absorb and to retain sufficient water. Though toxic 
concentrations of the salts of the heavy metals do not appreciably 
lower the vapor pressure above the medium, it is possible that these 
salts also act by decreasing the power of the cells to absorb water. 
A consideration of the factors which may be involved in bring- 
ing about the variations in toxicity in the different media leads to 
the suggestion of several possibilities. In the first place it is 
known that certain salts react ‘with sugars, starch and proteids. 
The resulting compounds if formed in a given medium would be 
expected to show properties different from the salt and different 
from other compounds that might be formed in still other media. 
Relatively little is known of these substances, but some of them 
have been studied and the conditions that favor their formation 
have been determined. 
In a solution of sodium hydroxide, cane sugar is converted into 
sodium saccharate (see Thomsen, 32). Saccharates of calcium, 
potassium and barium are also known (see Peligot, 24). All of these 
saccharates are formed by the action of the hydroxides of the differ- 
ent metals on cane sugar. The addition of ammonia to a solution 
of cane sugar increases the rotatory power of the solution and has 
been taken as evidence that a compound is formed between the 
sugar and ammonia (see Wilcox, 35). Copper and iron saccharates 
have also been reported (see Graham, 10). They are made by 
adding the chlorides to alkaline solutions of cane sugar. We can 
not, however, in the cases before us, attribute the variations in 
