260 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1908. 



important from a technological point of view, likewise carried in its 

 wake great consequences for scientific chemistry, for the investiga- 

 tion of the composition of this dye led to a synthesis, capable of 

 general application, of the derivatives of quinoline. In a like manner 

 the explanation of the constitution of rosaniline was very productive 

 in allowing the synthesis of numerous new compounds, among which 

 are found some of the most beautiful and valuable dyeing materials. 



The appearance of substantive azo colors, and finally of those known 

 as " sulj^honated dyes," has not occasioned the opening of any new 

 avenues of scientific investigation. These two accomplishments, how- 

 ever, are of the greatest importance in that they have provided new 

 methods for dyeing and printing and have completely revolutionized 

 these two ancient industries. 



Lastly, we may mention the new class of indanthrene colors in 

 which are united clear tints with an hitherto unknown resistance to 

 all destructive influences. 



It is the synthesis of indigo, however, that we must hail as the most 

 brilliant of all the conquests in the field of coloring materials. We 

 can still recall the day when the great event in chemical history was 

 made public and when every hand was extended in congratulation 

 for this masterpiece of scientific research. The struggle for a solu- 

 tion to this great problem cost twenty years of assiduous labor, but, 

 once solved, how well the new product of synthetic indigo has stood 

 the test beside the natural product backed by several thousand years' 

 use. 



There is no hope that this industrial triumph in the coloring field 

 will ever be surpassed. It is none the less certain, however, that this 

 industry has not yet attained the limit of its development. Our 

 reviews in the future will still record many achievements bearing 

 witness to the uninterrupted development of this interesting and 

 manifold branch of technology. 



We may consider the manufacture of synthetic medical prepara- 

 tions as an offshoot of the color industry which sprang up in the 

 period we are considering and which has already earned a position 

 of its ov/n. What brilliant results have been accomplished in this 

 field, also. What a beautiful gradation of development from com- 

 plex insufficiency to simple perfection can be witnessed in comparing 

 kairine and thalline on one side and antipyrine, phenacetine, and as- 

 pirine on the other. What a progress in the regulation of physio- 

 logical functions is evidenced in chloral hydrate and veronal. What 

 pains has not synthetic chemistry soothed by its activity in this field, 

 what ills has not it assuaged. 



The industry of artificial medicines is only one of a vast circle of 

 varied activities which we are in the habit of grouping together under 

 the collective term of preparation industries. To properly appreci- 



