436 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1957 



than a tentative priority to any one individual because the prospects 

 are still good that a diligent searcher may at any time unearth an 

 obscure reference showing that someone else has antedated one's 

 own "first." 



If one investigates the early history of the subject, he can see this 

 for himself. For a long time it was believed that Joseph von Gerlach 

 introduced the use of stains in microscopic work in 1858. Then it 

 was shown that Goej)pert and Cohn (1849) had preceded him. They 

 had, in fact, been antedated by Ehrenberg in 1838. Preceding all of 

 them was the Englishman Sir John Hill, who as early as 1770 had 

 used dyes, especially extract of logwood, to study the microscopic 

 structure of timber. Actually, however, as mentioned earlier, it was 

 Antony van Leeuwenhoek who was apparently the first to record the 

 use of a dye as an aid to microscopic observation. He was attempt- 

 ing to study the difference between the muscle fibers of a fat cow and 

 a lean one. To improve the visibility of the material under his 

 lenses, he soaked some fibers in saffron, a yellow dye obtained from 

 the crocus plant. Leeuwenhoek failed to follow up his observations, 

 or to perfect his technique, and so it was almost two centuries before 

 systematic efforts were made to use dyes or coloring matter as an aid 

 to microscopic observation. 



But if Joseph von Gerlach was not the undoubted originator of 

 staining, he certainly was its most articulate promoter, and for this 

 he definitely deserves credit. Gerlach (1820-96) was professor of 

 physiology and then of anatomy at the University of Erlangen during 

 most of his active life. He was a keen student of microscopic anatomy 

 and contributed much to the development of microscopic technique. 

 One of his greatest contributions was the discovery, independently, 

 and partly by accident, of the staining properties of carmine, a dye 

 obtained from the cochineal insect. He had been trying unsuccess- 

 fully to use this dye as a stain when on one occasion he inadvertently 

 left a section of brain in a dilute solution overnight. In the morning 

 he found a beautifully stained specimen. His previous failure had 

 obviously been due to the use of a highly concentrated solution. He at 

 once recognized the significance of this observation and proceeded to 

 develop its technical consequences. Not only that, but he so enthusi- 

 astically promoted its use among his colleagues and students that 

 despite the earlier use of carmine by others Gerlach's name was associ- 

 ated with the beginning of staining techniques in biology. 



It was at this most opportune time that William Perkin made his 

 epochal discovery of aniline dyes. As soon as the dyes were com- 

 mercially available, it was almost inevitable that someone would try 

 them out on a microscopic preparation. This happened in 1862 when 

 Beneke of Marburg, about whom little is known, employed acetic acid 



