vj PEEFACE 



In addition to the published researches which have been consulted, 

 I desire to acknowledge the help which I have obtained from the 

 following books : Lafar's Handbuch der technischen Mykologie, Newman's 

 Bacteriology and the Public Health, Green's Fermentation, and Muir 

 and Ritchie's Manual of Bacteriology. 



Further, I wish to acknowledge my indebtedness to the Rev. 

 Robert Barr, M.A., to Prof. L. A. L. King, M.A., and to other 

 friends for their valuable assistance during the compilation of this 

 work. 



DAVID ELLIS. 



Glasgow and West of Scotland 



Technical College, 



Glasgow, 190fl. 



