INTRODUCTORY AND EXPLANATORY. 



In addition to the Active Principles that are members of one or other of 

 the three classes specially dealt with, I have included some substances 

 that are liable to be met with in connection with these, or have bearino- on 

 the subjects under treatment. ° 



The term Alkaloid (or the letter A used for that word) has been 

 employed to denote any naturally occurring vegetable base ; this covers a 

 wider area than would the most modern application of the word which 

 restricts it to Pyridine and Quinoline derivatives, to the exclusion of such 

 a body as Caffeine. Of course, Salts of Ammonia and albuminoid decom- 

 position products cannot be comprised in this class (one or two of the 

 latter receive notice, however). 



The Glucoshlet! embrace those substances (other than tannins) that 

 yield sugar (with some other compound) when decomposed by the action 

 ot dilute acids or natural ferments. They are generally free from 

 Nitrogen, exceptions being Amygdalin, Solaniue, Indican, Linamarin, 

 Myronic Acid, and Sinalbni, the last two of which contain Sulphur also 



1 hemtter Pnndples are a very diverse group, as various in composition 

 as in their chemical reactions. They contain no Nitrogen, and yield no 

 sugar on treatment with dilute acids or otherwise. The name Awaroid 

 IS suggested for such bodies as these, in order to avoid confusion with 

 glucosides and alkaloids, so many of which are also bitter. Being verv 

 numerous and frequently of considerable importance, whilst generally 

 neglected in works upon organic chemistry, it has been thought desirable 

 to describe them fully. 



_ In conformity with the system adopted by the Chemical Society in their 

 journal, all alkaloids are spelt with the termination ine, whUst glucosides 

 and amaroids end in in, without the final e. 



The book consists of three parts (besides two indexes and sub- 

 indexes). 



* ^'^■'^'^xJ' '" Dictionary form, arranged upon a system which groups 

 together the constituents either of one plant or of a number of botanically 



or chemically allied plants, whilst retaining as far as practicable an alpha- 

 betical order. Supplementary indexes being provided, the manifest 

 inconveniences which a purely alphabetical method would occasion are by 

 these means avoided. 



^- In order that no time may be lost in finding any statement con- 

 cerning a given substance, the following rotation has been adhered to in 

 the enumeration of the properties and tests : 



Botanical Z»ctot7s.— Plants furnishing the compound or compounds, with 

 technical as well as popular names and botanical order. 



Parts of plant in which found. 



Bibliographical reference (names of investigators and details of published 

 researches). 



Each substance (when more than one) is then treated individually thus : 



General, Physical and Chemical Details.— ^ame and synonyms, class (A = 

 Alkaloid, B = Bitter Principle, G = Glucoside). 



Chemical formula. 



Crystalline form, etc. 



Melting point and effects of heat generally. 



Rotatory power (action on polarized light). 



Reaction (alkaline, neutral, or acid). 



Taste and odour (if any). 



Various : Character of salts, products of hydrolysis (action of boiling dilute 

 acids), physiological effect. 



Solubility in water, alcohol, ether, chloroform, benzene, petroleum ether, amyl 

 alcohol, carbon bisulphide, and sundry other solvents. 



Behaviour towards immiscible solvents. 



Reactions with precipitants, etc. (in this order) : 



1. Alkaline hydrates and carbo- 



nates. 



2. Ammonia. 



3. Lead acetate, neutral and basic. 



4. Tannic acid. 



5. Picric acid, C,;Ho(NOo)3'OH 



(Hager's reagent). ' 



6. Ferric chloride. 



