P7^esident's Address. 3 



can be found, than by taking a comprehensive view of the 

 functions of organic life. But not to dwell longer upon 

 this topic, I shall pass on to — . 



2d. That as a very large proportion of the substances 

 of our Materia Medica are derived from the vegetable 

 world, it is surely of importance that we should know 

 something of the characters and relations of the plants 

 which yield them. If any one should say that we can 

 easily prescribe rhubarb without knowing its botanical 

 source, or that it belongs to the Polygonacece, then I 

 answer that we can with equal facility prescribe Epsom 

 salts without any knowledge of its being sulphate of 

 magnesia ; but if the absence of the latter knowledge 

 would imply an ignorance of chemistry which would pre- 

 clude from the medical profession, on what ground can the 

 gross ignorance of botany be applauded and regarded as a 

 ground of congratulation ? Is it asserted that an acquaint ■ 

 ance with natural orders can teach us nothing bearing on 

 the medicinal character of the plant ? This only betokens 

 the ignorance of the asserter ; for does he not know that 

 A. P. de Candolle, as early as 1816, published a work 

 entitled " On the Medicinal Properties of Plants compared 

 with their External Characters and their Natural Classi- 

 fication," thus establishing a law which indeed Linnaeus 

 himself suggested, and which was accepted by the majority 

 of the men of science. The researches of Crum Brown 

 and Eraser, Cahours, &c., on ethyl- and methyl-strychnia, 

 have shown how a slight chemical change may entirely 

 alter the physiological actions, and have thus proved how 

 apparent contradictions to the above law, in the case of 

 Strychnos toxifera yielding curare, as compared with other 

 species of Strychnos, may be explained. But in a recent 

 paper. Professor Herlandt, by a careful, minute, and dis- 

 criminating process, has fully established the three follow- 

 ing propositions : — 



(1.) Botanic species and families which are similar in 

 their characters are also similar in the nature and pro- 

 perties of their constituents. 



(2.) The species which form the connecting link between 

 similar groups contain constituents belonging to the allied 

 families. 



