AUTHOR'S PBEFACE. vii 



I have sCssumed in my readers an acquaintance with the leading 

 principles of general and analytical chemistry, and have, there- 

 fore, passed over parts of the latter, such as ultimate and ash- 

 analysis, since these have been fully treated of elsewhere. Sub- 

 jects that have been discussed at length in my 'Ermittelung 

 von Giften,' and ' Chemische Werthbestimmung starkwirkender 

 Droguen,' have been referred to as briefly as possible. An ulti- 

 mate analysis is, of course, frequently necessary in order to 

 demonstrate the identity of a substance isolated during the 

 investigation with some other known body. I have, therefore, col- 

 lected analyses of the constituents of plants, and have arranged 

 them both alphabetically and according to the percentage of 



carbon they contain. 



THE AUTHOK. 



