IV PREFACE 



influence of Dr. H. H. Rusby, Professor of Materia 

 Medica, College of Pharmacy, Columbia University. 

 Dr. Rusby's labors have been a source of inspiration; 

 and association with him has been responsible for 

 whatever measure of success the writer has attained 

 in the field of microanalysis. 



For constructive criticism and generous aid in 

 revision of the manuscript, I am indebted to Fanchon 

 Hart, Instructor in Materia Medica, College of Phar- 

 macy, Columbia University, who by kindly help has 

 greatly expedited the issuance of this manual. 



Acknowledgment is also due the Bausch & Lomb 

 Optical Co., E. Leitz and the Spencer Lens Co., for 

 the use of illustrations and data from their several 

 catalogues. 



Colombia University, Q m iff. B. 



College of Phabmact. 

 November, 1920. 



