( 372 ) 



drops of toluene. In experimeiils with access of air, a regulated 

 current of air sterilised ^) and free from carbonic acid came iuto tlie 

 closed flask, and the issuing current of air passed first through a 

 calcium chloride apparatus and then through a potash-bulb (with 

 CaCl^ tube). The increase of weight of the potash bulb indicated 

 the amount of carbonic acid formed, whilst in some experiments 

 this was also sliowji qualitatively with baryta water. 



For the experiment in a hydrogen-atmosphere the flask was first 

 filled with hydrogen that had been purified with dilute-potash, 

 after which, with the necessary precautions the enzyme, a solution 

 of sugar and a few drops of toluene were introduced. Then during 

 the experiment a [)uriiied cun-cnt of hydrogen })assed through the 

 flask and carried the CO.^, which had been produced, into the potash 

 bulbs; at the end aii* free from CO^ passed through, in order to be 

 able to determine the increase in weight of the bulbs. 



The experiments always lasted 48 hours ^), only once did I deter- 

 mine the CO, produced in successive periods of 3 and 6 hours, but 

 found no great differences. Indeed the method was not suitable for 

 successive determinations with small intervals, since after terminating 

 the experiment by healing the liquid in the tiabk above 70° C, one 

 ought to pass the current through for a short time longer in order 

 to get all the carbonic acid into the potash bulbs '). 



The liquid in the flask was always boiled for a moment at the 

 end of the experiment and the first distillate was tested by means 

 of the iodoform reaction for alcohol, the result was always negative, 

 both in the aerobic experiments and in those in a hydrogenatmos- 

 phere *). 



Then the liquid was cooled, made up to a definite volume and 

 filtered. I determined the quantity of organic acid in the filtrate, 

 equally that of the glucose, the latter one before and after boiling 

 with dilute hydrochloric acid *). Control experiments, in which the 

 liquid was boiled immediately after mixing, gave the total quantities 



1) For this purpose the air passed through strong caustic potash, to which 

 some toluene had been added. 



-} The experiment with a preparation horn the spadices took place in daylight; 

 since organic acids in aqueous solutions are gradually decomposed by light, the 

 quantities found are somewhat too small. 



3) If traces of GO^ should remain behind, the result would naturally be too low. 



^) Only a few drops were distilled over. Generally the odour indicated traces of 

 butyric acid. 



5) The glucose determinations were made according to N. Schooel's method. 

 Ned. Tijdschrift voor Pharmacie 1899. The quantity after boiling with HGl was 

 generally as great as before boiling, the former values are given. 



