CHINOLINE AND ITS HOMOLOGUES. 379 



Chinoline has, however, been invested with an artificial interest, from a sup- 

 posed intimate connexion between it and quinine, and an equally supposititious 

 parallelism between the action of heat upon the last named alkaloid, and upon 

 the hydrated oxide of tetramethylammonium, while the real points of attraction 

 which it possesses have been neglected, or supposed not to exist. 



The first incorrect idea of the connexion between chinoline and quinine, may 

 be very briefly disposed of. It was founded upon the supposition that chinoline 

 was the sole product of the action of hydrate of potash, at a high temperature, 

 upon quinine. In this manner, it was easy to construct an equation by which it 

 was made to appear, that quinine, minus a certain number of equivalents of car- 

 bon, hydrogen, and oxygen, yielded chinoline. 



Another supposed connexion between the two alkaloids was a very beautiful 

 one, and one that, at the time when C 18 H 8 N was the received formula for chino- 

 line, could scarcely have failed to suggest itself to the eminent chemist, whose 

 particular train of research led him to examine the action of iodide of methyl 

 upon the natural and artificial alkaloids. It is well known, that iodide of tetre- 

 thylammonium, by treatment with oxide of silver, yields hydrated oxide of that 

 base, which is rendered obvious, by a glance at the following equation : — 



I + AgO + HO = N ^£s 0,HO + AgI; 



and if we follow out the same equation, substituting iodide of methyl-chinoline- 

 ammonium,* for iodide of tetrethylammonium, we find that at first sight, 

 C 20 H n N, I + Ag O + HO = C 20 H 12 N0 2 + Ag I 



v w - V m 



Iodide of Methyl- Quinine . 



^chinolineammo- 

 nium. 



appears a reaction likely to take place ;f unfortunately, however, there are two 

 reasons why it is impossible, the first being, that iodide of methyl-chinoline-ammo- 

 nium is represented by C 20 H 10 N, I, instead of C 20 H u N, I; and the other, that 

 the action of oxide of silver upon the methyl and ethyl compounds of the 

 nitryl bases of this class is more complex than would be supposed from the first 

 equation, and the known success of the reaction with the iodides of the ammonium 

 bases derived from the alcohol radicals alone. 



So much has been said about the artificial formation of quinine from the leu- 

 kol of coal-tar, that I have appended a few reasons for concluding that it is im- 

 possible by any analogous process to that previously described. Quinine, accord- 



* Supposing for the moment the old formula for chinoline (C 18 H g N) to be correct. 



f I have vainly searched through the Chemical Journals for any paper by Dr Hofmann, tending 

 to show the real nature of the action of oxide of silver upon iodide of methylchinoline. This has led 

 me to make the experiments detailed at page 392. 



