40 



NA TURE 



[December 7, 1899 



which, at the request of the Society of Apothecaries, the Com- 

 missioners had drawn up for the future government of the Chelsea 

 Physic Garden, in the ownership of which the Royal Society 

 had by the deed of grant of Sir Hans Sloane, a reversionary 

 interest. The Council appointed a Committee to consider the 

 Charity Commissioners' scheme, and this Committee having 

 reported to the Council in favour of the scheme, with certain 

 amendments which the Charity Commissioners expressed their 

 willingness to adopt, the Council have concurred in the scheme, 

 which provides for the maintenance of the Garden, under the 

 Charitable Trusts Acts, for the purposes of botanical study, 

 and gives to the Royal Society, among other Institutions, a 

 representation upon the Committee of Management. 



"Privileged" Candidates for Fellowship. 

 The attention of the Council having been drawn to the 

 regulations governing the election of Fellows under privileged 

 conditions, a Committee was appointed early in the year to 

 consider whether any alteration in them would be desirable. 

 The Committee have duly reported, and, in accordance with 

 their report, the Council have under consideration a modifica- 

 tion of the Statutes, enabling the Council to recommend to the 

 Society for election persons who either are Members of Her 

 Majesty's Privy Council, or have rendered signal service to the 

 cause of science, provided that not more than three such persons 

 shall be elected in any one year, the persons so recommended 

 to be selected by the Council by ballot in accordance with a 

 procedure to be established by Standing Orders of Council. 

 The Standing Orders which the Council propose to make 

 correspond in the main with the procedure for the adjudication 

 of the medals, but are still more stringent in character. 



In the evening the Fellows and their friends dined together 

 at the Whitehall Rooms. 



STEREOCHEMISTRY AND PHYSIOLOGY. 

 1 N a recent number of the Zeitschrift fiir physiologische 

 ^ Chemie, Prof. Emil Fischer has reviewed the facts by 

 •which, in conjunction with Thierfelder, he has sought to explain 

 the selective action exhibited by the enzymes either in effecting 

 fermentation or in producing hydrolysis. 



Pasteur was the first to show that a solution of racemic acid 

 becomes Irevo-rotatory in presence of penicillium, owing to the 

 destruction of the dextro-tartaric acid by the fungus — an observ- 

 ation which has been frequently utilised in the attempt to isolate 

 one of the optically active constituents of a racemic compound. 



Configuration and Alcoholic Ferment alion. — This selective 

 action is exhibited in a very marked degree by the beer yeasts 

 in producing fermentation of the carbohydrates. Of the eleven 

 known aldohexoses (glucose type) only the three natural pro- 

 <lucts are fermentable, viz. dextro-glucose, dextro-mannose and 

 ■dextro-galactose, and of the ketohexoses only dextro-fructose is 

 decomposed. 



All the yeasts susceptible of inducing fermentation transform 

 dextro-glucose, mannose and fructose with about equal velocity ; 

 but the action of yeast on dextro-galactose is slower, and cer- 

 tain species — Saccharoinyces apiculatus and produciivus — are 

 totally without action upon it. 



A comparison of the configuration of these four sugars will 

 exhibit the differences in molecular grouping. 



COH 

 I 

 HCOH 



HOCH 



I 

 HCOH 



I 

 HCOH 



COH 

 I 

 HOCH 



I 

 HOCH 



I 

 HCOH 



I 

 HCOH 



COH 



i 

 HCOH 



i 

 HOCH 



I 

 HOCH 



I 

 HCOH 



CHjOH 

 CO 



HOCH 



I 

 HCOH 



I 

 HCOH 



CH2OH CH2OH CHOII CH2OH 



rf-glucose. rf-mannose. rf-galactose. ^-fructose. 



In glucose, mannose and fructose the grouping of the H and 

 OH round the three lower asymmetric carbon atoms is the 

 same, but differs from that of galactose, a fact which may ac- 

 count for the slower fermentive action of the latter. The other 

 hexoses are not fermentable. The small difference in configur- 

 ation which suffices to arrest the action is seen in the case of 

 <f-talose, which only differs from (/-galactose by the position of 

 one hydroxyl group. 



NO. 157I, VOL. 61J 



COH 

 I 

 HOCH 



I 

 HOCH 



I 

 HOCH 



I 

 HCOH 



I 

 CH2OH 



rf-talose. 

 Configtiration and Zyinolysis of the Glticosides. — By the 

 combination of glucose with methyl alcohol, to form methyl 

 glucoside, a new asymmetric carbon atom is created, and conse- 

 quently two stereo-isomeric derivatives are possible. E. Fischer 

 has obtained from ^-glucose both modifications, which he terms 

 a and ;8 methyl (f-glucosides, also the corresponding a and j8 

 methyl / glucosides and similar products from the other aldoses. 

 Fischer has allotted to the a and ^ methyl ^-glucosides the fol- 

 lowing formulae. 



HCOCH3 



l\ 

 HCOH\ 



CH3OCH 



l\ 

 HCOH^ 



I 

 HOCH 



1/ 

 HC 



HOCH / 



\/ 

 HC ■ 



I I 



HCOH HCOH 



I I 



CH2OH CH2OH 



An aqueous solution of the emulsin of bitter almonds hydro- 

 lyses the /3 modification, but has not the least action on the a 

 modification. Exactly the reverse happens with an aqueous ex- 

 tract of dry yeast. In this case the o compound is hydrolysed, 

 whilst the /3 modification remains unchanged. The ethyl and 

 phenyl glucosides, which are only known in one modification, 

 iDehave like the a methyl compound, and probably belong to the 

 same category. Neither emulsion nor yeast affect the two methyl 

 /-glucosides. 



/^-galactose forms two methyl derivatives, one of which is 

 attacked by emulsin and the other by the enzyme of yeast, 

 but more slowly than the corresponding glucosides, the difference 

 in rate corresponding with that observed in fermentation. Neither 

 methyl rf-mannoside nor methyl /-mannoside is attacked by 

 emulsin or the enzyme of yeast. The second </- mannoside, 

 which would probably be hydrolysed by one or the other fer- 

 ment, is still unknown. The pentoses and heptoses are non- 

 fermentable, and their methyl glucosides are likewise indifferent 

 to both enzymes. 



The following is a list of natural and artificial glucosides. The 

 action of the enzyme is denoted by a -t- when it produces hydro- 

 lysis and by a - when it is without action. 



\ 



