320 SECTIONAL TRANSACTIONS.— B. 



Prof. Dr. L. Zechmeister. — The enzymatic cleavage of cellulose and 

 cellulose break-down products. Relationship between cellulose and 

 chitin{m collaboration with Dr.W.GRASSMANNandDr. G. Toth). 



An investigation of the action of enzymes on break-down products of 

 cellulose containing a comparatively small number of glucose units has 

 revealed unexpected relationships which suggest that the action of enzymes 

 is dependent not only on the nature and stereochemical arrangement of the 

 groups in the molecule undergoing reaction, but also on the chain length 

 of the molecule. This conception opens up a new field of investigation in 

 connection with the chemistry of enzymes, the exploration of which is 

 important in view of the new idea thus afforded of the relationship between 

 enzyme action and the chemistry of the polysaccharides. From Asper- 

 gillus extracts an oligosaccharase and a polysaccharase have been separated. 



Chitobiose, the break-down product obtained from chitin, yields an 

 acetyl derivative and has chemical properties which show it to be constituted 

 analogously to cellobiose, the corresponding break-down product of cellulose, 

 and it appears that chitin is to be regarded as built up of continuous chains 

 of chitobiose units, joined together in a manner similar to the cellobiose units 

 in cellulose. The observation that chitodextrine undergoes a rapid break- 

 down , when treated with emulsin , proves the presence of p -linkings in chitin . 



Prof. Dr. H. Staudinger. — The nature and size of the colloid particles 

 of cellulose and related substances. 

 The work of Haworth and his school has shown the mode of linking of 

 glucose units in cellulose. The question of how many such units are com- 

 bined in the molecule can be answered by investigating the nature and the 

 size of the colloid particles of cellulose dissolved in Schweizer's reagent or 

 of the acetate or nitrate in organic media. These colloid particles are the 

 molecules themselves and, contrary to McBain, Meyer and Mark, have not 

 a micellar character. This is shown by the examination of ' polymer 

 honaologous series ' of break-down products of cellulose, the lower mole- 

 cular members of which are recognised, by ordinary chemical methods, as 

 thread-molecules of different lengths. These products exhibit a relation- 

 ship between their molecular length and their viscosity in solution, which is 



expressed by the viscosity law : -^ = K»,.M, where 7]5p is the specific 



viscosity, c the concentration, K,„ a characteristic constant for each polymer 

 homologous series, and M the molecular weight. K,« can now be derived 

 from other viscosity measurements — e.g. in the paraffin series and in sub- 

 stances with 6-rings. 



These investigations were facilitated by the parallel study of synthetic 

 polymeric substances of known constitution. By these methods, cellulose 

 in Schweizer's reagent is found to have mol. wt. 120,000 — that is, 750 glucose 

 residues are combined in one molecule. The molecules are long threads 

 which in one dimension are 500 times longer than in the two others. This 

 provides an explanation of the colloid nature of cellulose solutions. 



Dr. E. L. Hirst. — Amylose and amylopectin. 



Analogues of cellulose, containing mutually linked glucose units, are 

 represented by starch and glycogen. But whereas in cellulose the units are 

 P-glucopyranose, in starch and glycogen they are a-glucopyranose, the model 

 of which does not permit of its forming a straight chain pattern such as is 

 possible with cellulose. No sure evidence has been available as to the size 

 of the molecular unit, and the situation has been rendered complicated by 



