626 KUNKEL: INFLUENCE OF STARCH, PEPTONE, AND SUGARS ON 
in fifteen hours. (2) It is able to use as a partial source of its 
food supply a rather large number of organic compounds. Went 
(6) has found that it grows well on media containing any one of 
the following substances: maltose, trehalose, raffinose, saccharose, 
cellulose, starch, fats, and proteids. This makes it especially 
suitable for experiments in which the organic part of the medium 
is to be varied. 
All of my cultures were grown in Petri dishes that were pre- 
viously immersed for at least ten hours in cleaning solution made 
according to Duggar’s method (1). In the preparation of media 
and for rinsing glassware redistilled water was used. 
In the tables that follow, the zero sign indicates that none of 
the spores on the medium in question had germinated, the minus 
sign indicates that germination and microscopic growth had taken 
place, while the plus sign indicates that growth was visible to the 
naked eye. All cultures were incubated at room temperature 
(about 22° C.)- 
In order to determine whether or not the toxicity of various 
salts to Moniha sitophila is influenced by sugars, starch, or pep- 
tone, each of these organic substances was used separately in 
testing the toxicity of the inorganic salts. I have designated the 
highest concentration of a salt that would. permit germination of 
the spores in a given medium, as the limit concentration for that 
medium. A number of preliminary experiments were made to 
determine the approximate value of the limit concentration for 
each salt in each medium used. The results obtained in a final 
set of experiments are shown in the tables given below. 
EXPERIMENTAL 
Monilia will produce a considerable growth of mycelium and 
will ripen spores on a medium made by adding 5 grams of corn- 
starch to 95 cubic centimeters of redistilled water. The results 
obtained in a series of experiments in which different inorganic — 
salts were added -to this medium are shown in TABLE I.. The 
concentrations varied from 1.33 molar for potassium nitrate to 
.000004 molar for zinc nitrate. 
The table shows at a glance the sorte toxicity of the 
nitrates used, in the order in which they are arranged in the table 
