638 KUNKEL: INFLUENCE OF STARCH, PEPTONE, AND SUGARS ON 
SUMMARY 
1. The degree of toxicity of barium nitrate, aluminum nitrate, 
ferric nitrate, and urea nitrate to Monilia sitophila depends on the 
organic substance contained in the media in which these salts 
are offered. 
2. Barium nitrate is more toxic in peptone media than in 
starch media, while aluminum nitrate and ferric nitrate are more 
toxic in starch media than in peptone media. 
3. Barium nitrate has practically the same toxicity in starch 
media that it has in either glucose or fructose media. Its toxicity 
in peptone media is the same as its toxicity in galactose media. 
4. The toxicity of aluminum nitrate in galactose media is the 
same as its toxicity in starch media. Its toxicity in fructose is 
much greater than in peptone or glucose. 
5. The toxicity of ferric nitrate is approximately the same in 
starch as in glucose, fructose, or galactose. Its toxicity in peptone, 
however, is much less than in any of the other substances used. 
6. Urea nitrate is four times more toxic in starch media than 
in peptone media. 
7. The toxicity of ammonium tartrate is practically the same 
in starch as in peptone media. 
8. If the limit concentration of zinc nitrate in starch media be 
taken as 1, then the limit concentration of the other nitrates in the 
same kind of media may be expressed, by comparing equimolecular 
concentrations, approximately by the following numbers: silver 
nitrate, 5; ferric nitrate, 26; aluminum nitrate, 52; ammonium 
nitrate, 1,520; urea nitrate, 1,600; calcium nitrate, 16,560; and 
potassium nitrate, 53,200. 
This work was done in the laboratories of the University of 
Missouri and under the direction of Dr. George M. Reed, to whom 
I am greatly indebted for encouragement and advice. 
COLUMBIA UNIVERSITY, New York City 
_ BIBLIOGRAPHY 
1. Duggar, B. M. Fungous diseases of plants, 12, 13. 1908. 
2. Fluri, M. Der Einfluss von Aluminiumsalzen auf das Protoplasma- 
Flora 99: 81-126. 1908. 
z- Lipman, C. B. Toxic and anti oxic effects of salts as related to 
