Dixon and Atkins — Osmotic Pressures in Plant-Organs. 11 



Turning now to the yeast in Nos. 595, 598, 612, the osmotic pressure of 

 the juice is much higher than that of the beer, corresponding in two cases to 

 a difference in freezing-point of about 0'5°. In these oases the yeast was 

 separated from the beer by centrifuging to remove adherent liquid as 

 completely as possible, and was then frozen. This process occupies some 



Tart.e II. 



time. In No. 612, where it was effected as rapidly as possible, less than one 

 hour elapsed between the separation and the freezing in liquid air. In this 

 case the divergence between the osmotic pressure of the yeast and of the beer 

 was the greatest observed. In Nos. 607 and 610 yeast was allowed to stand 

 for six hours and twenty-four hours respectively after separation before 

 freezing. The results here show a diminution in pressure, owing most 

 probably to respiratory changes, so that it has fallen slightly below that of 

 the beer from which it was removed. From Nos. 610 and 611 it appears that 

 this decrease in osmotic pressure takes place whether the yeast is kept dry or 

 suspended in water. This rapid falling off shows very likely the normal rate 

 of consumption of carbohydrate with the resulting increase in conductivity. 



