434 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1957 



elsewhere, which had been producing the madder plant, had been con- 

 verted to the growing of food crops. A few years later the synthesis 

 of indigo forced the elimination of another agricultural product. 



By 1874 Perkin felt that he had had enough of chemical technology. 

 He therefore sold out his interests for about 100,000 pounds and re- 

 tired to devote himself to pure research. His later work included 

 the synthesis of coumarin, an odoriferous substance with the smell of 

 new-mown hay. With this discovery he laid the basis for the syn- 

 thetic perfume industry. He also studied the formation of unsat- 

 urated fatty acids and did considerable fundamental work on the sub- 

 ject of magnetic rotation. 



Perkin married twice and had three sons and four daughters. The 

 sons all became chemists, and the eldest, William Henry Perkin, Jr., 

 became one of England's greatest organic chemists. The elder Perkin 

 received many honors during his lifetime. He was elected a Fellow 

 of the Royal Society in 1866, named a Royal Medallist in 1879, and 

 was awarded the Davy Medal in 1889. In 1906 the Jubilee of the Dis- 

 covery of Mauve was celebrated in both England and America. In 

 1907, shortly before his death, Perkin was knighted by his king. 



We turn now to a consideration of the effect of the discovery of 

 aniline dyes on biology and medicine. This is in fact one of the most 

 instructive episodes in the history of science, since it illustrates so 

 beautifully the unexpected way in which a discovery in one field of 

 science may profoundly influence developments in other areas. In 

 1856 when the first aniline dyes were made no one could have antici- 

 pated that within a few years a whole family of coloring agents de- 

 rived from coal tar would be of assistance in solving many funda- 

 mental problems in cellular biology and pathology and would play a 

 major role in the discovery of the causes and cures of many infectious 

 diseases. 



To appreciate the full significance of the discovery of aniline dyes 

 on the biological and medical sciences let us glance quickly at the 

 status of knowledge in these subjects a century or more ago. 



The way in which aniline dyes exerted their influence on biology 

 and medicine was first of all as an aid to the microscope. These dyes 

 were discovered at a moment when they could be effectively used to 

 help solve certain important problems for biologists and medical men. 

 To appreciate this it will be useful to recapitulate very briefly a few 

 facts about the history of the microscope and microscopy. Several 

 periods may be distinguished. Although the microscope was in- 

 vented sometime between 1590 and 1608 (the exact date is uncertain) 

 little important scientific work was done with it at first. The first 

 important phase from 1660-1723 was the time of the "Classical Mi- 

 croscopists." These included Marcello Malpighi, who discovered the 



