VI PREFACE 



out because the Micro-Chemistiy of Dr. E. M. Chamot, which has recently appeared 

 treats these and indeed all matters pertaining to the chemico-physical side of 

 microscopy in an adequate manner. 



As a closing word it may be said that even an elementary book like this depends 

 for its production upon many helps. The work of others must be looked for in a 

 great library; special knowledge in allied departments must be utilized through 

 the help of colleagues; apparatus and ideas can only be put in graphic form by the 

 deft hand of the artist; and perhaps most important of all is the advice and criti- 

 cism of the friend. All of these helps the author has had in abundance, and he 

 feels grateful to each helper. 



SIMON HENRY GAGE 

 Cornell University 

 February 22, 1917 



