1892. ] NEW YORK ACADEMY OF SCIENCES. 115 
research, for he had already made oxindole from phenylacetic acid, 
which in turn is made from some of the coal-tar products. The 
synthesis is complete, although tedious. 
The artificial formation of oil of mustard is another triumph 
of synthetic organic chemistry. In distilling glycerin and oxalic 
acid the chief product obtained is formic acid; but the rest of the 
products of decomposition were unknown until Tollens, the chemist, 
undertook to investigate them. He found that, besides formie acid, 
there was also produced a considerable quantity of allyl alcohol. 
Now this alcohol is one of the principal constituents of oil of mus- 
tard, but nobody knew of an economical method of preparing it 
until Tollens showed that it could be produced from glycerin and 
oxalic acid. It can now be made in any quantity and ‘readily con- 
verted into oil of mustard. 
Citrie acid, usually made from lemons and limes, can also be 
made artificially. 
Glycerin is the starting-point. 
Glycerin is treated with chlorine, and gives what is called a 
dichlorhydrin. This dichlorbydrin is oxidized with chromic acid, 
and gives an acetone ; this acetone is treated with hydroeyanic acid, 
then with hy drochloric acid, then with sodium, then with potas- 
sium cyanide, and finally with hydrochloric acid, which gives citric 
acid. 
Of course, the process is too complicated to be useful; but the 
_ synthesis or building up of the organic acid from glycerin is an 
accomplished fact. 
Taurine, the acid of bile; salicin; piperidine, the active principle 
of black pepper; uric acid; tyrosine, a product of the spleen, liver, 
urine, ete.; vanilline, the aromatic principle of the vanilla bean ; 
cumarine, of the tonka bean ; daphnetine and umbelliferone, natural 
glucosides ; and other bodies that it is unnecessary to mention, are 
all the products of modern organic synthesis. 
Furthermore, in the search ‘after the constitution of organic com- 
pounds we are often led to discover bodies, hitherto unknown to 
man, with many new and valuable properties. 
At the beginning of the lecture I spoke of the use of distillation 
by the old chemists and apothecaries as a means of obtaining the 
active principles of substances. During the seventeenth cen tury a 
man named Dippel applied this process to certain fetid animal oils, 
obtained from stag’s horns, and the product was long known in the 
apothecary’s store as Dippel’s oil or bone-oil. 
About the year 1846, Anderson, a Scotch chemist, discovered in 
this Dippel’s oil certain basie oily bodies that resembled ammonia 
in their property of containing nitrogen. Little attention was paid 
to this fact. 
In the year 1834, Runge, a German chemist, discovered a series 
of bases in the distillates from coal-tar; and about the same time, 
or a little later, Greville Williams, an English chemist, located these 
