176 PLANT AND ORGANIC CHEMISTRY 



purposes should grow under natural conditions. Cultivation 

 of plants tends to diminish in quantity or to eradicate their 

 noxious or medicinal principles. According to Professor Vogel, 

 hemlock does not yield coniin in Scotland; cinchona plants 

 are nearly free from quinine when grown in hothouses; and 

 tannin is also found in the greatest quantity in trees which 

 have a direct supply of sunlight. Wild belladonna plants 1 

 contain more alkaloids than the cultivated. 



Until within a comparatively very recent date, there were 

 no schemes for vegetable analyses equivalent to Fresenius's 

 " Manual for Inorganic Substances." The irregularities of the 

 methods of individual investigators in plant chemistry made 

 it extremely difficult for students to follow this kind of analy- 

 sis. The deficiency has been filled by the admirable book on 

 " Plant Analysis," by Professor Dragendorff, of Dorpat, Russia. 

 This book has appeared in a French translation, 2 and the 

 first edition of an English translation 3 was published a year 

 before. Professor Dragendorff does not claim to have written a 

 perfect book. He offers a scheme, which, if followed, supple- 

 mented by well-known or original methods in the study of 

 special or new compounds, will give the student a knowledge 

 of the chemical constituents of a plant which he could not well 

 obtain by a non- systematic scheme. 



Dragendorff 's scheme has been criticised as encouraging a 

 mechanical method of work on the part of the analyst, but I 

 think any student, on working for the first time on a new drug, 

 by this method will find that he will be thrown very much on 

 his own resources, and that the scheme serves him merely as 

 a chain and anchor in a sea of novelty and uncertainty. It 

 is indeed the most complete scheme for plant analysis which 

 we have. 



The scope of plant analysis is well outlined by Dragendorff 

 in his introduction, and if my time permitted me I could not 



1 "The Alkaloidal Value of Cultivated and Wild Belladonna," by Girrard. 

 Pharm. Jour, and Trans., vol. xv, p. 153. 



2 Encyclopedic Chimique, tome X, "Analyse chimique des Vegetaux." 

 Traduit de 1'allemand et annote, par F. Schlagdenhauffen. Paris, 1885. 



8 Plant Analysis, by G. Dragendorff. Translated from the German by 

 H. G. Greenish. London, 1884. 



