20 



NATURE 



[November 14, 1912 



mulated as to the nature of oxydases, more particu- 

 larly whether they are to be regarded as enzymes. 



A further contribution from the Reading laboratory 

 by Mr. W. N. Jones dealt with the distribution of 

 o.xydases in white flowers. Many white flowers con- 

 lain a chromogen which becomes coloured (brown) 

 when acted upon by an oxydase or peroxydase. The 

 author considers that this chromogen is probably not 

 identical with that responsible for the colour in the 

 flower of coloured varieties of the same species. The 

 chromogen may be associated with oxydase or with 

 peroxydase only, or it may be altogether lacking from 

 the flower. It is possible to extract this chromogen 

 after destroying the oxydase by boiling, and use the 

 solution as a test for oxydase in the same way as 

 benzidine. 



A paper by Mr. A. Compton gave a summary of 

 Prof. Bertrand's investigation of the action of 

 enzymes on the complex glucoside vicianin, a con- 

 stituent of Vicia angustifolia, a rare species of tare. 



On Monday, September 9, the section divided, the 

 physical chemists taking part in a joint discussion 

 with Section A, opened by Dr. F. A. Lindemann, with 

 a paper on the atomic heat of solids. This is reported 

 more appropriately in the proceedings of Section A. 

 The organic chemists devoted the morning entirely 

 to the subject of carbohydrates. It is a remarkable 

 fact that in spite of the great importance of the 

 sugars as foodstuff's and the part thev plav in plant 

 and animal economy, rur knowledge of them is still 

 of the scantiest. The complexity of the sugar 

 molecule and the experimental difficulties which beset 

 the worker in this field render progress but slow, 

 and any researches, even if they be of the type classed 

 by scoffers as compound making, will be of the utmost 

 value if they serve in any way to indicate new methods 

 of attacking the subject or lead to greater certainty 

 of the knowledge of chemical structure. The 

 problems of the sugars are certainly quite as complex 

 as those of the proteins ; their solution must be accom- 

 plished before any real attack is made on the origin 

 of life. 



Three communications were received from the St. 

 Andrews laboratory. The first, by Prof. Irvine and 

 Mr. A. Hynd, dealt with synthetic aminoglucosides. 

 Aminoglucose, or glucosamine, as it is usually called, 

 constitutes the simple unit which, when polymerised, 

 forms chitin, the horny constituent of the shell of the 

 lobster, and which occurs in place of cellulose in the 

 cell walls of many of the lowly organisms. Hitherto 

 the properties of glucosamine have been but little 

 investigated. Some of the experimental difficulties 

 have been overcome now by the use of bromotriacetyl- 

 glucosamine, which enters into reaction with widely 

 different types of hydroxy compounds. The 2-amino- 

 glucosides thus obtained corresoond with amino 

 derivatives of the natural glucosides, which exist in 

 such diversity in plants. Many of the synthetic sub- 

 stances are not simple amino compounds, but their 

 nitrogen atom is associated with the contiguous 

 oxygen atom to form a four-membered betaine ring : 

 tbey are thus brought into relation with the betaines 

 of plants. Others, again, particularly those in which 

 a benzene grouping is present, do not show this 

 neculiarity of ring formation. This paper gave rise 

 to a full discussion. 



In the following paper, by Prof. Irvine and Miss 

 B. M. Patterson, an account was given of the experi- 

 mental study of the constitution of mannitol tri- 

 acetone. _ It is impossible to arrest the condensation 

 of mannitol with acetone at intermediate stages, but 

 by carefully regulated hydrolysis the acetone molecules 

 can be removed in stages. The constitution of the 

 intermediate compounds was determined by methyla- 



NO. 2246, VOL. qo] 



tion and subsequent hydrolysis. The acetone residue 

 is shown to be attached through oxygen to two con- 

 tiguous carbon atoms, but the order in which the 

 acetone residues were removed was quite une.xpected. 

 It is impossible to discuss the problem without enter- 

 ing into complex stereochemical considerations, but 

 as a result of the work and the methods used in it, 

 a deeper insight has been gained into the sugar 

 molecule than had previously been the case. 



The third paper, by Prof. Irvine and Dr. J. P. 

 Scott, dealt with the rotatory powers of partially methy- 

 lated glucoses. By applying stereochemical con- 

 siderations based on the optical rotatory power of the 

 isomeric glucoses and glucosides, configuration 

 formulae for the a and 3 isomerides have been deduced 

 which are in agreement with those previously sug- 

 gested by E. F. .Armstrong. Certain regularities in 

 the rotatory power of the a and 3 forms of the 

 partially methylated glucoses were pointed out : these 

 conform to the rule postulated by Hudson. 



Dr. W. S. Mills described a simple method of pre- 

 paring acetyliodoglucose, a compound which has in 

 the meantime been prepared by Fischer in another 

 way. By the action of copper hydride on this, a 

 crystalline compound has been obtained which is con- 

 sidered to be the acetyl derivative of a diglucose, 

 in which, however, the two molecules are united 

 through carbon, and not through o.xygen as in the 

 natural sugars. 



Dr. Harden followed with a summary of the know- 

 ledge of hexose phosphate, which, as his researches 

 have shown, plays so important a part in the pheno- 

 menon of alcoholic fermentation. Dr. Harden dis- 

 cussed the equations which have been suggested to 

 explain the action of the phosphate during fermenta- 

 tion : he was inclined to accept that which involves 

 the rupture of glucose into two three-carbon com- 

 pounds, one of which is further broken down into 

 carbon dioxide and alcohol, whilst the other unites 

 with a similar compound from a second molecule of 

 sugar to form hexose phosphate. 



The sitting concluded with a paper on nomen- 

 clature by Dr. E. F. Armstrong. It is suggested to 

 number the six carbon atoms in glucose thus : — 



CH,OH.CH(OH).CH(OH).CH(OH).CH(OH).CHO, 



instead of using Greek letters as at present. This 

 avoids the confusion arising from the common use 

 of a and 13 to indicate isomerism in the groups 

 attached to the asymmetric carbon atom in position i. 

 Prof. Irvine concurred in this suggestion. .Attention 

 was also directed to the uncertainty introduced in 

 the nomenclature of optically active compounds by 

 using the prefixes d and 1, sometimes to denote the 

 sense of the rotation and sometimes to denote the 

 relationship in configuration to (i-glucose. 



The greater part of Tuesday's proceedings were 

 devoted to papers dealing with subjects of import- 

 ance to organic chemists — namely, the migration of 

 groups and the laws of substitution in the benzene 

 ring. 



The methods by which chemists are wont to deter- 

 mine the structure of a compound and the precise 

 position in it of certain groups all depend on the 

 displacement of this group bv another at some stage 

 of the investigation. It is important to know that 

 such substitution takes place in a simple manner, 

 and that the new group is not introduced in some 

 altogether different position. Unfortunately for our 

 theories, it was found by Walden some few years back 

 that in the case of optically active compounds such 

 rearrangement is the rule rather than the exception. 

 In consequence, when some new compound is ob- 

 tained from an optically active substance, it is fre- 



