326 



NATURE 



[November 4, 1920 



to cover more. Why, then, proceed to build up on 

 an equation an elaborate metaphysical structure? 

 And, especially, why imagine that the success of the 

 Einstein equation proves the observed velocity of light 

 to be the same whatever the motion of the observer? 

 If the observer thinks, and if he is aware of the 

 FitzGerald-Lorentz contraction, he will know that 

 such a proposition is not true ; he will know that the 

 velocity of light is not equal in all directions in a 

 relatively drifting medium, that the wave-front is 

 not concentric to the observer, and that the Michelson 

 experiment gives no proof of anything of the kind. 



The uniformity of the aether makes the obtaining 

 of positive results difficult; there seem to be always 

 compensations. .Some day we may be able to evade 

 this experimental difficulty, but meanwhile, if we 



choose to make the supposition that motion of the 



observer can never have any directly observable effect, 

 or that one set of axes of reference is necessarily 

 equivalent to every other and indistinguishable by 

 any kind of superficial observation, then we seem to 

 be in accord with present experience. From that 

 supposition definite consequences can, with adequate 

 skill, be deduced, and the deductions have been sub- 

 jected to successful verification. 



But if on the strength of that remarkable achieve- 

 ment some enthusiasts proceed to formulate proposi- 

 tions which by ignoring the motion of the observer 

 and all its consequences complicate the rest of the 

 universe unduly, then, however much we mav admire 

 their skill and ability, I ask whether they ought not 

 to be regarded as Bolsheviks and pulled up. 



Emil Fischer's Contributions to Organic Chemistry.* 

 By Dr. M. O. Forster, F.R.S. 



EMIL FISCHER was born on October 9, 1852, at , 

 Euskirchen, and his death on July 14, 1919, I 

 occurred at a time when every element of constructive j 

 and harmonising influence was most sorely needed. | 

 Since 1892, when he succeeded von Hofmann, he | 

 had fulfilled the duties of professor and director of I 

 the chemical institute in the University of Berlin 

 with increasing distinction. Physically commanding, 

 his authority rested on the solid foundation of natural 

 dignity. The brisk, upright carriage marked the man 

 of action ; the glowing eyes revealed his attitude of 

 constant, keen inquiry ; it was impossible to escape 

 his contagious enthusiasm. 



Fischer addressed himself to organic chemical 

 research at the opening of its brightest epoch. Having 

 described the preparation of phenylhydrazine in 1875, 

 he devoted many succeeding years to developing the 

 transformations of that remarkable substance. During 

 this period he also collaborated with his cousin. Otto 

 Fischer, in elucidating the constitution of rosaniline 

 tases, their first joint paper appearing in 1876. It 

 Is noteworthy that, in spite of his early interest in 

 the chemistry of these and other colouring matters, 

 and notwithstanding his association with von Baeyer, 

 beginning in Strasbourg and continuing until he left 

 Munich to occupy the chair of chemistry at Erlangen 

 in 1882, he nevertheless resisted the temptation to 

 succeed Caro as director of research in the Badische 

 factory, although at this time (1883) the colour industry 

 was in the early flush of its active growth. 



When reviewed as a chapter which is closed, 

 Fischer's work must be regarded as having estab- 

 lished upon a firm basis the fundamental science of 

 biochemistry. The assimilation of carbon dioxjde and 

 water by plants, the variety and complexity of sac- 

 charide molecules proceeding therefrom, the degrada- 

 tion of the proteins, the probable course of their 

 synthesis from amino-acids, and the power of assem- 

 blage or of disruption exerted by enzymes on all these 

 tjuilding materials of the animal and vegetable king- 

 doms are subjects which Fischer not merely illu- 

 minated, but was the first to place in coherent 

 arrangement and intelligible sequence. Recognition 

 of the fact that all this was accomplished, not by 

 revolutionary processes or theories, but by skilful 

 development of the thoughts ^nd operations expanded 

 by Liebig, von Hofmann, Pasteur, and von Baeyer, 

 IS perhaps the highest tribute which can be paid to his 

 genius. 



Fischer's association with the branch of chemistry 



1 Synopsis of the Emll Fischer Memorial Lecture delivered before the 

 Chemical Society on Oclober 28. 



NO. 2662, VOL. 106] 



which first brought him fame began in 1884, when 

 he discovered phenylglucosazone, produced from 

 glucose, fructose, and mannose by the action of 

 phenylhydrazine. At that tinje only two aldohexoses 

 (glucose and galactose) and two ketohexoses (fructose 

 and sorbose) were known and recognised as straight- 

 chain pentahydroxy-derivatives. .According to the 

 requirements of van't Holf's theory, a pentahydroxy- 

 aldehyde of this class, in which five carbon atoms are 

 each associated with one hydroxyl group, should 

 appear in siyteen stereoisomeric forms, eight of these 

 being enantiomorphs of the remainder. The bare 

 statement that Fischer and his collaborators elucidated 

 the configuration of twelve such isomerides, most of 

 which they synthesised for that purpose, although 

 perhaps an accurate summary of his opening achieve- 

 ment, conveys but a nebulous impression of the 

 character and amount of the labour involved. More- 

 over, his discovery of -y-methylglucoside in 1914, and 

 the consequent recognition of cyclic relations distinct 

 from that occurring in a- and ^-glucose, have opened 

 the way to a multitude of contingent isomerides, 

 those of d-glucose alone numbering ten. Thus Fischer 

 not only elaborated his own sugar chemistry, but also 

 added to this the foundation of a new carbohydrate 

 classification. 



The directive influence on Fischer's work in this 

 field was the discovery, in association with Tafel in 

 1887, of a- and /3-acrose. The former sugar he 

 identified with dZ-fructose, whilst /3-acrose is now 

 recognised as d/-sorbose. The above-mentioned syn- 

 thetical operations, and many others connected with 

 pentoses, tetroses, and artificial sugars containing 

 more than six atoms of carbon, were effected by 

 means of the cyanohydrin reaction. Pasteur's method 

 of separating optical antipodes, and the discovery that 

 when a monobasic sugar-acid is heated with quinoline 

 at 140° C. the configuration of the carbon atom 

 adjacent to the carboxyl grouo becomes epimerised 

 (1890). 



One of the most remarkable achievements in a 

 series unsurpassed by anv organic chemist was 

 Fischer's , synthesis of the principal constituent of 

 Chinese tannin. In 1852 .Strecker had shown that 

 gall-nut tannin is a compound of grape-sugar and 

 gallic acid, but latterly the conclusion had become 

 discredited, and tannin was regarded as consisting 

 mainly of dlgallic acid. This was synthesised in iqo8 

 by Fischer and found to be crystalline, although 

 astringent, and in 1912 he showed that the principal 

 constituent of Chinese tannin does give glucose on 

 hydrolysis. By a series of complex synthetical opera- 



