June 26, 1908] 



SCIENCE 



975 



a very little more chemistry than I did, 

 who asked me what I thought of "the new 

 chemistry." Not being willing at that 

 time to confess my ignorance, I believe I 

 said I thought very well of it, and in the 

 silent watches of the night I often found 

 myself wondering what was meant by "the 

 new chemistry." Arriving in Germany, I 

 found that the old masters like Liebig and 

 Wohler would have nothing to do with the 

 new chemistry, while the younger teachers 

 in the same universities used the new sys- 

 tem. In the end the law of Avogadro pre- 

 vailed, and now it is generally, I fear, 

 taught dogmatically, and the evidence upon 

 which it rests is lost sight of. 



The conception that proved to be most 

 fruitful during the period immediately fol- 

 lowing the acceptance of the law of Avo- 

 gadro was that of the constitution of com- 

 pounds as first clearly set forth by Kekule 

 in his great "Handbook of Organic Chem- 

 istry." Soon after the appearance of this 

 book the majority of the younger chemists 

 were ardently engaged in trying to deter- 

 mine the constitution of chemical com- 

 poimds. Results came rapidly. The de- 

 termination of constitution led, further, to 

 efforts to build up natural substances arti- 

 ficially in the laboratory and factory. One 

 of the first great successes in this line was 

 the artificial preparation of the coloring 

 matter of madder, known as turkey red, 

 or alizarin. Since then achievements in 

 synthetical chemistry have been innumer- 

 able. Great industries have been devel- 

 oped in the wake of these efforts and there 

 seems to be no end to the possibilities. Per- 

 haps the most sensational of the successes 

 in synthetical chemistry is that which has 

 culminated in the artificial preparation of 

 indigo. It took about a quarter of a cen- 

 tury to work out that problem— a problem 

 that is of great interest not only to the 

 chemist, but to the agriculturist, the polit- 

 ical economist and the anthropologist. 



Let us not forget that, while Kekule 's 

 clearly expressed views gave the principal 

 impetus to the work on constitution that 

 led in turn to the work in synthetical chem- 

 istry, the way had been prepared by a long 

 line of predecessors, among whom should be 

 especially remembered Berzelius, Gay-Lus- 

 sac, Laurent, Liebig, Wohler, Dumas, Will- 

 iamson and Frankland. Kekule did not 

 lead a revolution, he helped an evolution. 

 The work in the field of synthetical chem- 

 istry is still progressing, and results as 

 valuable as ever are being obtained. The 

 problems under investigation are in general 

 more difficult of solution than those that 

 have already been solved. I need only 

 mention in this connection the magnificent 

 researches of Emil Fischer, of Berlin, on 

 the synthesis of proteins, the complex sub- 

 stances that enter so largely into the com- 

 position of living things. It is of the 

 highest importance that the chemistry of 

 these substances should be worked out. 

 The more we know about them, the better 

 shall we be able to understand the mechan- 

 ism of the living organism. 



Within the last twenty-five or thirty 

 years that branch of science which is called 

 physical chemistry, and sometimes chemical 

 physics, has been largely developed, and 

 this has contributed to the advance of 

 chemistry in many ways. The beginnings 

 of physical chemistry are to be found, how- 

 ever, in the very beginning of the last cen- 

 tury. Bertholet's work on "Chemical 

 Statics," which appeared in 1801, may 

 fairly be regarded as an important con- 

 tribution to the subject, but more impor- 

 tant, because more fruitful, was the work 

 of Guldberg and Waage on the law of 

 mass action which appeared in 1867. Since 

 then, through the labors of Ostwald, Van't 

 Hoff, Arrhenius and a host of others, phys- 

 ical chemistry has taken an independent 

 position, and it may now be regarded as a 

 new branch of science, occupying a field 



