EXCHANGE 



The Influence of Calcium, Magnesium 



and Potassium Nitrates upon the 



Toxicity of Certain Heavy 



Metals Toward Fungus 



Spores 



DISSERTATION 



Submitted to the Board of University Studies of the Johns 

 Hopkins University in conformity with the require- 

 ments for the degree of Doctor of Philosophy 



By 

 LON A. HAWKINS 



Baltimore, June, 1913 



[.PHYSIOLOGICAL RESEARCHES VOL. I, NO. 2, AUGUST, 1013] 



