1922] WALTON—AFRICAN SORREL 167 
Table IV gives the figures relating to the acidity of water extracts 
of both the fresh and dried material, and specific acidity values 
computed for pure solutions of potassium binoxalate of the same 
respective normalities (titrable acidities) as the water extracts. 
TABLE V 
PERCENTAGE OF OXALATES AND EQUIVALENTS IN LEAVES 
Calcium 
bag wa (C20.) tal ( nf mn 
minus ac 
Sample on acidity of ge deren of Ria vaca se ) C20,), in | ves 
water extract Rereilt table 111 column 4 equivalent 
ae minus | of (C.0,) in 
si omg column 3 preceding 
column 
No. 38339, small leaves 
ee SSN. one a 1.82 1.25 1.69 0.44 0.64 
Seer yy aa gks 19.09 13.10 17.80 4-70 6.80 
No. “38840, large leaves 
wn any Mos oe cas 2.05 1.41 1.73 0.32 0.47 
EP MOn Say sian) Parte 19.22 13.20 16.20 3.00 4.40 
The data in table V are derived entirely from determinations 
made on the dried material. In the second and last columns the 
data from tables III and IV are correlated to show the percentage 
amounts of salts of oxalic acid presumably present in both the 
fresh and dried leaves. The percentages given for calcium oxalate 
are for the anhydrous salt, for convenience in comparing with data 
in pharmacological literature. 
The assumption that most of the oxalate is present as potassium 
binoxalate and calcium oxalate (as the monohydrate) is substan- 
tiated by additional information obtained through the kindness of 
Dr. Wuerry. The work of Mr. DEvEL on total soluble oxalate 
also checks in a striking manner the figures for binoxalate. 
CRYSTALLOGRAPHIC-OPTICAL EXAMINATION 
WuHERRY, who examined some of the dried and ground material 
by polarized light, under a petrographic microscope, identified 
humerous crystals of potassium binoxalate, and a smaller number 
of crystals of calcium oxalate monohydrate in groups. The potas- 
sium binoxalate crystals were readily identified, because of their 
characteristic of having a relatively low alpha index. WHERRY 
