The influence of starch, peptone, and sugars on the toxicity of various 
nitrates to Monilia sitophila (Mont.) Sacc, 
OTTO KUNKEL 
INTRODUCTION 
Winogradsky and Omeliansky (7) found that the addition of 
.05 per cent of glucose or asparagin to nitrite-media hindered the 
development of the nitrate-bacteria. Peptone at a somewhat 
greater concentration was also detrimental. These substances 
are widely used in the preparation of culture media, but have 
been given little attention by investigators of the problems of 
toxicity. 
Fluri (2) has reported that the salts of aluminum render the 
protoplasm of Spirogyra and other water plants permeable and 
are, therefore, injurious to these plants. He found, however, 
that if glucose, glycerin, or isodulcitol are mixed with the alumi- 
num salt it loses its power of rendering the protoplasm permeable. 
Thus the toxicity of aluminum salts to these plants depends upon 
whether or not glucose, glycerin, or isodulcitol are present in the 
medium. Quite recently Schreiner and Skinner (4) have reported 
that the toxicity of the organic poison cumarin is counteracted by 
phosphates, thus indicating a relation between the organic and 
the inorganic part of the medium. 
In view of these results it has seemed worth while to investigate 
the influence of organic substances on the toxicity of inorganic 
salts. It has been my object to determine the toxicity of different 
salts in the presence of certain inorganic substances that are much 
used in the preparation of culture media. 
MATERIAL AND METHODS 
I have used the fungus Monilia sitophila in all of my experi- 
ments and have found it well suited to my purpose. Some of the 
things that recommend it are as follows: (1) It is a rapid grower. 
On a favorable medium at room temperature it will produce spores 
