1922] WALTON—AFRICAN SORREL 159 
The presence of considerable amounts of oxalic acid, as found in the Bureau 
of Chemistry, in the form of soluble oxalates, as well as calcium oxalate, suggests 
caution. It is a well known fact that some people are especially susceptible to 
’ . c . an d i : . 4 ee Pe 4% : Se a 
salic ari 
leaves are by no means rare. It appears possible, however, that by the addition 
of calcium carbonate the soluble oxalates may be precipitated, and thus t 
major portion of the objectionable ingredient may be eliminated. Another 
means suggested, and possibly equally effective to make the product available 
for general consumption, would be the removal of the water in which the material 
has been soaked and boiled. At any rate, we have here a product which may 
be placed on the market, and which may be used as a substitute for spinach and 
other greens, but the identity and characteristics of which should be known to 
the consuming public and especially the food officials concerned with the wel- 
fare of the people 
Several plants started in the vicinity of Washington in 1920 
made vigorous, healthy growth (fig. 1). Because of the promising 
character of the plant as a source of summer greens, it was decided 
to submit a sample to the Bureau of Chemistry for a determination 
of its oxalic acid content. The suggestion was made, however, that 
in order to decide the question of its wholesomeness it was essential 
that both the total (titrable) acidity and specific acidity (H-ion 
concentration) of a water extract of the material be determined, as 
well as the total oxalate content. These determinations were 
undertaken in conjunction with the colorimetric determination of 
specific acidity in certain feeding stuffs. 
TABLE I 
DIMENSIONS OF LEAVES OF SAMPLES IN MM. 
SAMPLE NO. 38330 SAMPLE NO. 38340 
DIMENSION 
Largest | Smallest —_ Largest. | Smallest — 
- Length of blade.......... 195 75 149.0 260 230 249 
Extreme breath ofblade..| 150 45 118.0 250 200 220 
ips of date MONE eas 120 40 86.5 140 100 125 
On August 5, the plants in Washington being at a suitable stage 
of growth, a sample of about one pound of fresh foliage was analyzed. 
Practically all of the material obtained consisted of sound, crisp 
leaves with petioles. As there were two distinct sizes of leaves, 
the material was divided into two samples. The dimensions of the 
leaves constituting these samples are given in table I. 
