ADDBEfciS. 19 



which has given to organic chemistry the impetus which has overcome 

 so many experimental obstacles, and given rise to such unlooked-for 

 results. Organic chemistry has now become synthetic. In 1837 we were 

 able to build up but very few and very simple organic compounds from 

 their elements ; indeed the views of chemists were much divided as to 

 the possibility of such a thing. Both Gmelin and Berzelius argued that 

 organic compounds, unlike inorganic bodies, cannot be built up from 

 their elements. Organic compounds were generally believed to be special 

 products of the so-called vital force, and it was only intuitive minds, like 

 those of Liebig and Wohler, who foresaw what was coming, and wrote in 

 1837 strongly against this view, asserting that the artificial production in 

 our laboratories of all organic substances, so far as they do not constitute 

 a Living organism, is not only probable but certain. Indeed, they went a 

 step farther, and predicted that sugar, morphia, salicine, will all thus be 

 prepared ; a prophecy which, I need scarcely remind you, has been after 

 fifty years fulfilled, for at the present time we can prepare an artificial 

 sweetening principle, an artificial alkaloid, and salicine. 



In spite of these predictions, and in spite of Wiihler's memorable 

 discovery in 1828 of the artificial production of urea, which did in 

 reality break down for ever the barrier of essential chemical difference be- 

 tween the products of the inanimate and of the animate world, still, even 

 up to a much later date, contrary opinions were held, and the synthesis of 

 urea was looked upon as the exception which proves the rule. So it came 

 to pass that for many years the artificial production of any of the more 

 complicated organic substances was believed to be impossible. Now the 

 belief in a special vital force has disappeared like the ignis fat uus, and 

 no longer lures us in the wrong direction. We know now that the same 

 laws regulate the formation of chemical compounds in both animate and 

 inanimate nature, and the chemist only asks for a knowledge of the con- 

 stitution of any definite chemical compound found in the organic world 

 in order to be able to promise to prepare it artificially. 



But the progress of synthetic organic chemistry, which has of late 

 been so rapid, was made in the early days of the half-century only by 

 feeble steps and slow. Seventeen long years elapsed between Wohler's 

 discovery and the next real synthesis. This was accomplished by Kolbe, 

 who in 1845 prepared acetic acid from its elements. But then a splendid 

 harvest of results gathered in by chemists of all nations quickly followed, 

 a harvest so rich and so varied that we are apt to be overpowei-ed by its 

 wealth, and amidst so much that is alluring and striking we may well 

 find it diflBcult to choose the most appropriate examples for illustrating 

 the power and the extent of modern chemical synthesis. 



Next, as a contrast to our picture, let us for a moment glance back 

 again to the state of things fifty years ago, and then notice the chief steps 

 by which we have arrived at our present position. In 1837 organic 

 chemistry possessed no scientific basis, and therefore no classification of a 

 character worthy of the name. Writing to Berzelius in that year, Wohler 



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