B.— CHEMISTRY. 55 



important compounds, in the same way as Chevreul had much earlier 

 investigated the fats. Such was Baeyer's work on uric acid and its 

 derivatives. Emil Fischer, after a short period of work on triphenylme- 

 thane, devoted the labours of a lifetime to the purines, the simpler 

 carbohydrates, the proteins, and the tannins. 



As a result of Fischer's work the new science of biochemistry was 

 firmly established in the beginning of the present century, and the year 

 1906 marked its recognition in three countries, when three new journals 

 first appeared : the Biochemische Zeitschrift in Germany, the Biochemical 

 Journal in Britain, and the Journal of Biological Chemistry in America ; 

 the fijrst named absorbed Hofmeister's Beitrage zur chemischen Phrjsiologie 

 und Pathologic, already a competitor of Hoppe-Seyler's Zeitschrift. The 

 interest of German organic chemists in substances of general biological 

 importance may be further illustrated by Willstatter'swork on chlorophyll, 

 carotin, the anthocyanins and enzymes, by Windaus' investigations on 

 the sterols, by Wieland's work on the bile acids and by Hans Fischer's 

 study of the porphyrins, which recently resulted in the synthesis of 

 hsemin. 



British organic chemists appear to be more interested in theoretical 

 problems. I find that during the years 1927 and 1928 about 580 papers 

 on organic chemistry were pubhshed by the Chemical Society, consti- 

 tuting much the largest portion of the Journal. Of these rather less than 

 20 per cent, may be said to deal with natural products and were inspired 

 largely by W. H. Perkin (himself a pupil of Baeyer) and by Perkin's 

 pupil, Robinson. About 45 per cent, of British papers on organic 

 chemistry are more or less directly concerned with such theoretical 

 questions as stereo-chemistry, the nature of valency, reactivity, tautomer- 

 ism, and the remaining 35 per cent, deal with the synthesis of new com- 

 pounds devoid of theoretical and biological interest, although occasionally 

 having practical importance. German organic chemists seem to be more 

 interested in natural products. I estimate that of the organic chemical 

 papers in the Berichte for 1928 about 40 per cent, are concerned directly 

 or indirectly with such substances. It should not be supposed that 

 organic chemical theory is wholly unconnected with biology. Two 

 examples out of many will show the contrary. When a protein is 

 ' racesimed ' as far as possible, by Kossel's method, by leaving it for 

 some weeks at 37° in half-normal alkali, it is found that certain amino- 

 acids retain their optical activity and these Dakin has assumed to be the 

 ones with free carboxyl groups, situated at the ends of chains. The 

 others undergo racemisation probably because in their case tautomerism 

 is possible : 



— CO . NH . CR'H . CO . NH . CR"H . COOH 



It 



— CO . NH . CR' : COH . NH . CR"H . COOH 



On subsequent acid hydrolysis the amino-acid NHj. CR'H. COOH would 

 be racemic, but NH2.CR"H.C00H optically active. Dakin's views were 

 first applied by Dudley and Woodman to show a structural difference 

 between the caseinogens from cow's milk and sheep's milk, which had 



