AUTHOR'S PREFACE. 



WHILST engaged in collecting the material for my ' Ermittelung 

 von Giften,' I formed the intention of utilizing the knowledge 

 then acquired of the alkaloidal and other constituents of plants to 

 improve and extend the present methods of plant analysis. In 

 accordance with this intention I subsequently discussed in my 

 1 Chemische Werthbestimmung ' the detection and estimation of 

 the active principles of some powerful drugs, and at the same 

 time promised further communications on allied substances. 



In the meantime, I gradually became convinced of the need of 

 devising a process of analysis that should include as many as 

 possible of the more important constituents of plants. Such a 

 process was, I thought, a desideratum, as I had frequently ob- 

 served that the methods of examination published in some of 

 my researches were adopted by other chemists in cases in which I 

 myself should have deviated from them. 



This consideration was mainly instrumental in inducing me to 

 carry my plan into execution more rapidly than was originally 

 contemplated. No one can be more thoroughly aware than I am 

 myself of the insufficiency of the material at present available for 

 the construction of a systematic process of analysis, nor can any- 

 one be more conscious of the necessity for sifting and improving 

 the contents of the following chapters. I may, however, be per- 

 mitted to remark that in proposing to my pupils subjects for 

 scientific investigation, I have never lost sight of the plan I had 

 formed, and I have been able to benefit by the results of upwards 



