IV PREFACE 



not been written for advanced scholars, but is simply in- 

 tended for kindergarten use, as it were. In furtherance of 

 this design, care has been given to explain many things so 

 simple that they would seem to be self-evident to those 

 already familiar with the requirements of Photo-Micro- 

 graphy, but which, alas, are often insurmountable obstacles 

 to the beginner ; a feature quite ignored in all the works 

 on the subject which have come under my notice. With 

 this explanation of its scope and purposes, the little work 

 is put forth accompanied by the earnest hope that it may 

 prove to be a useful aid to many an earnest gleaner in the 

 ever-broadening field of Photo-Micrography. 



My earnest thanks are due, and herewith expressed, to 

 the many kind friends who have aided my efforts in the 

 "long ago " by precept and practice. Among them I 

 would especially name my old-time friend, Dr. A. Clifford 

 Mercer, of Syracuse, New York, and Dr. Wm. M. Gray, 

 of the Army Medical Museum, Washington, D. C., each 

 of whom has so largely contributed to the advancement of 

 Photo-Micrography, to its present important condition of 

 comparative perfection. My thanks are also due, in like 

 measure, to the publishers, whose liberality, experience 

 and good taste have done so much toward presenting the 

 little volume in its present attractive form. And, I may 

 add in conclusion, that should it meet with the hoped-for 

 approval at the hands of my readers, it will probably be 

 followed by a much fuller and more elaborate treatise on 

 the same subject, which has been in course of preparation 

 for several years. 



PHILADELPHIA, PA.. July 4, /0oa. 



