THE ALUMNI JOURNAL 113 



was obtained 0.226 Gni., from (b) (0.245 Gm.) 0.2098 Gm. ; a loss 

 of 0.0325 and 0.0352 Gm., respectively. 



From these experiments it results that indeed no pure quinine 

 sulphate is precipitated, and even after purifying by a second pre- 

 cipitation, as in (5) (a) and (b) no pure quinine sulphate is 

 obtained, as (6) (a) and (b) show, there still being a loss of 0.0325 

 and 0.0352 Gm., while pure quinine sulphate, under the same cir- 

 cumstances, as (2) shows, only gives a loss of 0.0108 Gm. Further, 

 Mr. Duncan considers that the precipitation of quinine sulphate, 

 in the presence of sodium sulphate, is independent of the other 

 cinchona alkaloids and of other conditions, except that the quinine 

 sulphate is more soluble in the sodium sulphate solution at higher 

 temperatures. 



The following experiments show that, when the quinine sulphate 

 is not precipitated under the most favorable conditions (a lower 

 temperature and a relatively high concentration of pure quinine 

 sulphate), the quantity, corresponding to the solubility, will not 

 crystallize out. Various quantities of pure anhydrous quinine sul- 

 phate were dissolved alone and with o.ioo Gm. of each of the 

 other alkaloidal sulphates and 10 Gm. of sodium sulphate in 100 Cc. 

 of water. 



Temperature 11° 



(I) (2) (3) (4) (5) (6) 

 Gm. quinine sulphate dis- 

 solved alone 0.017 0-034 0.052 0.059 0.117 0.239 



Gm. crystallized out after 



-24 hours o o o 0.07 0.088 0.224 



(I) (2) (3) (4) (5) 



Gm. quinine sulphate dis- 

 solved with the other 

 alkaloids 0.017 0.030 0.042 0.060 0.084 



Gm. crystallized out after 



24 hours C o o o 0.047 



In my opinion, the method of Duncan cannot be used for esti- 

 mation of the quinine in bark. Perhaps the method can be of 

 some utility, if the pharmacist wishes to separate the greater part 

 of quinine contained in the total alkaloid of the bark, or extract it 

 in cases where it is not necessary to obtain the substance quite 

 pure. It will thus give him a rough idea of the quinine content 

 of his drug. 



