Dixon and K'm.ui^— Extraction of Zymase by Means of Liquid Air. 5 



little toluene was used. Under £ and C the activity of the same sample of 

 yeast extracted by liquid air is given. 



Correction for dilution shows a total evolution of CO2 amounting to 

 0'33c.o., 0'38c.c., 0-34 c.c. per gramme of undried yeast in A, B, and C 

 respectively. 



In this case, allowing for the dilution of the liquid obtained by maceration, 

 its activity is again practically identical with that obtained by the liquid air 

 method. 



Some of the same yeast furnished a comparison of the method described 

 by Q-iglioli (2) ; 100 g. of the solid yeast was mixed with 5 c.c. of chloroform. 

 The mass became semi-fluid and frothed so vigorously that some 2 c.c. of the 

 fluid was lost. After six hours' standing 100 c.c. of the fluid was centrifuged, 

 and yielded 36 c.c. liquid, including chloroform. To 30 c.c. of this 12 g. of 

 sugar was added, and it was set to ferment. Its activity, which was great 

 at first, rapidly decayed. 



Experiment 4. 



Time. Volume of 



hr. min. CO2. 



10 ... 20-2 



No further fermentation. 



This is equivalent to 0'22 c.c. of COj per gramme of yeast. It is possible that 



maceration for a shorter period would yield a more active liquid, or perhaps 



the same result might be attained by using a smaller amount of chloroform. 



The generally low activity of the juice extracted by all these methods 

 from the yeast at our disposal suggested that possibly the enzyme was 

 impaired during the extraction. In the following experiment it was sought 

 to render the zymase more stable by furnishing it with fermentable material 

 immediately on its exit from the cells. With this object acccordingly, to 

 67 grammes of this solid yeast, while still frozen, was added a solution 

 containing 23 c.c. of water, 18 g. of sugar, and a little toluene. Experience 

 had showed that 67 g, of yeast would yield about 23 c.c. of yeast-juice ; 



