PREFACE 



For scientific work, it is desirable to get in the microscope 

 the sharpest and most ''contrasty" images possible with the 

 apparatus at hand. There are several dozen adjustments, 

 or variations of methods, each of which will add slightly to 

 the perfection of the image in the microscope. Alone, each 

 of these slight improvements may not seem worth making; 

 but combined they may cause a decided difference in the 

 brilliancy and crispness of the microscopical image. In 

 this book, the most important of these methods have been 

 brought together from the original papers, and to them have 

 been added the results of the writer's experience gained in 

 years of continuous work with the microscope. 



The author desires to thank especially Prof. Dr. H. 

 Siedentopf, of Jena; Dr. H. Hartridge, of Cambridge; and 

 the firms of C. Zeiss, E. Leitz, Watson and Sons, Bausch 

 and Lomb, Spencer Lens Company, and the Eastman 

 Kodak Company; for reprints or catalogues, and other 

 information. Dr. C. W. Metz and Dr. M. Demerec, of 

 the Carnegie Institution of Washington, have also given 

 welcome assistance. 



Dr. R. Chambers, of Cornell Medical College, kindly 

 read about half the original chapters and made many useful 

 suggestions, especially as to style. Dr. C. B. Bridges, of 

 Columbia University, also read some of the first part and 

 offered helpful criticisms. Mr. H. N. Ott, of the Spencer 

 Lens Company, was good enough to give advice with regard 

 to the chapter on the Greenough Binocular. The well- 

 known microscopist. Dr. N. A. Cobb, of the U. S. Depart- 

 ment of Agriculture, also gave suggestions with regard to 

 several chapters. Mr. L. W. Hoshour, California agent 

 of C. Zeiss, read the original draft and made useful criti- 



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