ANILINE DYES — LEIKIND 431 



it ended in failure since, with laboratory quantities, the yield was 

 insignificant. Larger amounts of pure anthracene were finally ob- 

 tained from a tar distillery and Perkin tried to nitrate this. Again he 

 failed. As a matter of fact, it was 25 years before the problem was 

 finally solved. Nevertheless, Perkin did, without realizing it then, 

 produce anthraquinone by the action of nitric acid on anthracene. 

 Anthraquinone happens to be the parent substance of alizarin, the red 

 dyeing principle of madder, which Perkin later had a hand in 

 synthesizing. 



Despite these failures, Perkin had now learned a great deal of 

 chemistry, and Hofmann made him his assistant. Hofmann was him- 

 self a most enthusiastic and stimulating teacher, and through him 

 Perkin was able to meet most of the scientific leaders of Britain and 

 the Continent when they visited the Eoyal College of Chemistry. 

 Thus by the age of 18 he already had a vast knowledge of contempo- 

 rary chemistry and a mature insight into its problems. Since Perkin's 

 duties at the College left him little time for independent research he 

 fitted up a small laboratory at home where he could work evenings 

 and during vacation. It was there that he made his first great 

 discovery. 



Hofmann, in the annual report of his laboratory for the year 1849, 

 had suggested that the time was ripe for an attempt to synthesize 

 quinine. This drug, it will be recalled, is the principal alkaloid of 

 cinchona, the bark of the cinchona tree, native to certain areas of 

 South America. It has long been used for the treatment of fevers, 

 especially of malaria. For centuries the drug was used simply in 

 the form of the powdered bark of the tree or as an extract or infusion. 

 Then in 1820 Pelletier and Caventou of France succeeded in isolating 

 quinine from the bark as an alkaloid in which form it gained an in- 

 creased popularity as a drug. At the same time chemists became 

 interested in synthesizing this compound, but without success. Never- 

 theless Professor Hofmann felt that the state of chemical knowledge 

 of the mid-nineteenth century justified another attempt at the synthesis 

 of quinine. In 1849 he wrote: 



It is a remarkable fact that naphthalene, the beautiful hydrocarbon of which 

 immense quantities are annually produced in the manufacture of coal gas, when 

 subjected to a series of chemical processes may be converted into a crystalline 

 alkaloid. This substance, which has received the name of naphthilidine, con- 

 tains 20 equivalents of carbon, 9 equivalents of hydrogen and 1 equivalent of 

 nitrogen. Now if we take 20 equivalents of carbon, 11 equivalents of hydrogen, 



1 equivalent of nitrogen and 2 equivalents of oxygen as the composition of 

 quinine, it will be obvious that naphthilidine, differing only by the elements of 



2 equivalents of water, might pass into the former alkaloid simply by the assump- 

 tion of water. We cannot, of course, expect to induce the water to enter merely 

 by placing it in contact, but a happy experiment may attain this end, by the 

 discovery of an appropriate metamorphic process. 



