THE CHEMIST AS A CONSTRUCTOR. 805 



judge by the way of its production, is not likely to contain any 

 ingredients found in living plants. The preparation of salicylic 

 acid from the products of coal-tar was discovered by Kolbe about 

 twenty years ago, inducing a more thorough study of the proper- 

 ties of this acid, from which it was found to be one of the most 

 valuable remedies for rheumatic complaints and for gout. Thus 

 one discovery often becomes the source of a whole series of new 

 ones, and may prove a blessing to mankind in the most unexpected 

 and various ways. 



Few people know what xanthin is. The name, indeed, rep- 

 resents a body of neither commercial nor industrial significance. 

 Scarcely anybody else but chemists and physicians knows that it is 

 a substance which, in a small amount, is found in muscles, in the 

 liver, brain, and certain other organs of the animal body. But little, 

 therefore, does he who enjoys a cup of cocoa, coffee, or tea, fancy 

 that the beneficent, animating effect of these beverages is due to 

 the methyl compounds of xanthin, contained as theobromine in 

 cocoa-beans and as caffeine, in coffee-beans and in the leaves of tea 

 and several other plants. Both theobromine and caffeine can 

 readily be prepared from xanthin, the products having exactly the 

 same physiological effect as the natural compounds. 



The line of products of organic life which have been built up 

 artificially from their constituents includes representatives of 

 many groups of compounds, although they are not equally numer- 

 ous in all of them. A large number of vegetable acids may be 

 synthetically prepared. The volatile oils of bitter almonds and 

 mustard, as well as the coloring matters indigo and alizarin, be- 

 sides being prepared from plants, are obtained from other sources 

 by chemical processes ; but, since their original production de- 

 pends on fermentative actions, to which the material is subject- 

 ed, they can not justly be classed among natural products. In 

 some groups of natural organic compounds our efforts to obtain 

 them by synthesis have hitherto almost utterly failed. Our 

 knowledge of alkaloids, many of which, by their great physio- 

 logical effects, are of prominent therapeutic importance, has ad- 

 vanced so far as to permit us to convert some of them into others — 

 for instance, to transform morphine into codeine ; but, with the ex- 

 ception of conine, which Ladenburg claims to have synthetically 

 obtained, and conhydrine, prepared by Hoffmann, both of which 

 are contained in hemlock (Conium maculatum), no success of con- 

 sequence has been registered. Nevertheless, as the knowledge of 

 their chemical structure has been cleared up to a very considera- 

 ble degree, we may expect that, by continued researches, ways for 

 their artificial manufacture will be found out. 



Many chemical discoveries were made by accident; com- 

 pounds of valuable properties were found by researches under- 



