INTRODUCTION. Xlll 



Pleasant as it would have been to add a histori- 

 cal outline of the development of micro-chemistry, 

 I have thought best not to do so, partly that the 

 book might be kept within proper limits as to size, 

 partly because that treatment of the subject 

 would more properly find place in a theoretical 

 and comprehensive text-book than in a compact 

 guide for purely practical use. 



