576 



Mr. A. Gordon SaJai 



[March 29, 



small qiiautities of succinic acid and glycerin always accompany their 

 formation, aud in attempting to state thi?; in the form of an equation, 

 Monoyer satisfactorily accounts for the liberation of oxygen. Thus — 



4(C,Hi,0,) + 3H.,0 = C,H,0, + eC.H.O. + 2C0, + 0. 



(Glucose) 



(Succinic Acid) (Glycerin) 



Various opinions have been expressed as to whether tlie presence or 

 absence of oxygen does actually influence the decomposition of sugar 

 and the formation of yeast to the extent indicated by Pasteur. Adolf 

 Mayer, whose opinion upon questions connected with fermentation is 

 justly regarded with great respect, made a series of experiments from 

 which he inferred that the influence was by no means as great as was 

 supposed ; but Schiitzenberger pointed out what certainly looks like a 

 flaw in his method of working, and would induce hesitancy in accept- 

 ing his conclusions. The great difficulty is to ensure the complete 

 permeation of the fermenting fluid by oxygen, which has a tendency, 

 if not corrected, to exercise its influence only upon layers or strata in 

 the fluid. It is found that the rate of fermentation greatly influences 

 the depth to which oxygen will permeate and diffuse, aud that a slow 

 fermentation favours efficient admixture. These conditions have 

 been brought under control by Hoppe-Seyler in a most ingenious and 

 satisfactory mauner.* His experiments upon the poiut in question 

 may be thus stated and tabulated : — 



Experiment. 



Units of 



Sugar 



decomposed. 



Units of 

 Alcohol 

 formed. 



Remarks 



1. C0.> absorbed and re- 



placed by O uniformly 

 diffuseci. 



2. Air above fermenting I'O 



fluid replaced by CO 2, 

 which was also passed 

 in during fermenta- 

 tion instead of O. | 



3. Normal fermentation 2-74 



Few budding cells ; cell con- 

 tents very granular; alco- 

 holic distillate strotvjly 

 acid. 



2*05 { Cell contents normal; alco- 

 holic distillate /t'e6/^ acid. 



4 '70 ] Cell contents normal; alco- 

 holic distillate faintly 

 acid. 



Now, from what has been said it will be understood, indeed it 

 follows, that the amoimt of carbonic anhydride evolved is a measure 

 of the extent to which the decomposition of the carbohydrate has 

 been carried by the alcoholic ferment. But, in order that this state- 

 ment may hold good, it is necessary that whenever the carbonic 

 anhydride is measured, there shall always be present in the fer- 

 menting fluid an excess of the solution of carbohydrate ; for Pasteur 



* Festschrift von Felix Hoppe-Seyler. Karl J. Trubuer, Strasburg, 1881. 



