'258 



It', oil the otliei' hand, we could fnrtlier the hydrolysis, and thus 

 accelerate the "transformation in time" which showed itself in many 

 cases, a positive proof would be given. 



Since, however, traces of NaOH already form a tine granular 

 precipitate, such an expei-iment seems to be excluded from measurement. 



The chemical complications, which in particular for iron-salts are 

 so numerous, constantly impede tiie investigation of these salts. 



Zurich Juli 1914. Phi/sikgebaiide des Eklyenüssisclien 



PolytechniLums. 



Microbiology. — "A microsaccliarimeter" . By Miss. H. J. van 

 LuTsiiNBURG Maas aiid Prof. G. van Itkkson Jk. (Communicated 

 by Prof. M. W. Beuerinck.) 



In the conscientious and extensive work of A. J. Kluyvkr: "Bio- 

 chemisclie suikerbepalingen"') (Biochemical Sugaranalysis) a fermen- 

 tation-sacchari meter is described, which enables us to quantitative 

 fermentations under perfect sterile circumstances. The quantities of 

 the different fermentable sugars, possibly at the same time present, 

 are to be calculated from the quantities carbonic acid, produced in 

 such an apparatus from a fixed volume liquid by different ferments. 



The rich material, which Ki.uyvf.r published, shows in a convincing 

 way, how this apparatus gives a most satisfactory and at the 

 same time simple solution for the problem of quantitative sugar- 

 determinations by means of the fermentation-method. Such a solu- 

 tion has in spite of the researches of many predecessors never been 

 found. 



The application of this method in studying biological questions, 

 from which Kluyver gives already some interesting examples, promises 

 most important results. 



By no means the fermentation-saccharimeter, whose description 

 will follow, will be able to supersede tlie apparatus, used by Ki.uyvkr. 

 The latter will always be preferred when accuracy is required 

 and a sufHicient quantity of the sugars is to be had. The reason 

 why, will be explained later, we only mention it here, because the 

 applicability of the here described method is justified by the results, 

 found with the apparatus of which Ki-uyvkr gives the description. 



In the first place some remarks may follow on this last appara- 

 tus and the limits of what can be attained will be indicated. 



1) Published by E. .1. Brill at Leiden, 1914. 



