148 EXPLOITATION OF PLANTS 
up on other bases derived from coal tar, and hence from 
fossilised plants. 
Cocaine and Piperine (01) 
Piperine (’94) 
| i Nicotine (’03) 
| ip 
a 
Dyes Conine (’86) “(Quinine : 
“| Cinchonine Papaverine, 
[fo Strychnine) | etc. 
Aniline Pyridine Quinoline 7, 
a | ge “a Isoquinoline 
7 Coal Tar. 
The accompanying table shows the coal tar bases of 
séveral familiar alkaloids. Those from the pyridine 
base have already been synthesised at the dates given. 
The quinoline derivatives have not yet been synthe- 
sised.* They are more complex even than the pyridine 
alkaloids, and include quinine, strychnine, ete. 
These results are of the first importance, both theoreti- 
cally and practically, as they pave the way for the better 
understanding of the action of the drug. We are still 
very far, however, from being able to correlate chemical 
constitution and physiological action. The tentative 
suggestion that the presence of OH groups is associated 
with antiseptic properties, and of NH, with narcotic 
properties, is not always supported by clinical experi- 
ence—notably in the sulphonal series, in which nar- 
cotism does not increase according to expectation with 
the number of ethyl groups present in the substances. 
Synthesised drugs are sometimes cheaper than the 
natural product, but, on the other hand, even the 
x 
