[Vol. 10 

 52 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Next, the glucose equivalent of the 13.2 mgms. copper is esti- 

 mated by interpolating in Shaffer's table of copper-glucose equiv- 

 alents, and finally, the amount of glucose consumed or used by 

 the organism is found by determining the difference between the 

 amounts of glucose recovered in the control and in the culture. 



Where amounts of sucrose are given they were determined as 

 follows : 



96 : 100 : : A : X, 



where the reducing ratio 



Glucose 



Invert sugar 



0.96, 



and A is the invert sugar ("glucose") value obtained by titration 

 and calculation, and X equals the true glucose value. 



Then : 



360 : 342 : : X : Y, 



where 360 is the molecular weight of 2 molecules of dH^Oe 

 and 342 is the molecular weight of Cn.H-O u . Then, where X 

 equals true glucose value determined above, Y equals sucrose 

 consumed. Fructose and galactose consumption were calculated 

 from the "glucose" values obtained, using the reducing ratios of 

 these sugars as given by Browne (12) : 



Glucose 

 Ratl ° Fructose = °- 92 > 



_ . Glucose 



Ratio — TT-y— t = 0.90. 



Galactose 



Consumption of lactose and maltose is directly determinable, 

 since both these sugars are reducing sugars. Consumption of 

 lactose, maltose, dextrin, and starch, as glucose, was determined 

 by hydrolyzing portions of both control and culture solutions 



(see "Methods," p. 47). For well-known reasons no attempt 

 was made to calculate consumption of dextrin and starch as 

 such, nor was it thought to be w r orth while to convert the galac- 

 tose-glucose value obtained by titrating the hydrolyzed lactose 

 into glucose. It should be borne in mind that the glucose values 

 given for dextrin and starch w T ere derived by multiplying the 

 glucose value obtained by titrating the hydrolyzed product by 0.9. 

 Without doubt the figures in the tables representing consump- 



