SPECIFIC ACIDITY OF WATER EXTRACT AND OXALATE 
CONTENT OF FOLIAGE OF AFRICAN SORREL’ 
GEORGE PELHAM WALTON 
(WITH ONE FIGURE) 
Foreword 
This report is submitted, not so much as a contribution to the 
accumulated data on the composition of the leaves of Rumex 
abyssinicus Jacq., as for the purpose of directing the attention of 
food and drug analysts to a comparatively simple procedure by 
which much of value may be learned about the source of the acidity 
in certain acid materials, with the minimum expenditure of time 
and effort. The scheme outlined in this paper has already been 
applied by the writer to a study of dried apple pomace and pectin 
pulp, with gratifying results, and it is believed that it should prove 
of value in the study of other feeding stuffs of an acid character. 
Material examined 
Among the plants brought to the United States for further study 
by the Office of Foreign Seed and Plant Introduction of the United 
States Department of Agriculture in 1919 was a native African sorrel, 
Rumex abyssinicus Jacquin.? The stock was brought from Angola, 
Portuguese West Africa, where the foliage is reported to be used as 
greens for human food. Dr. DAvip Farrcutp states as follows: 
Preliminary trials at various points in this country have shown this species 
to possess distinct promise as a summer vegetable. By sufficient parboiling 
it is distinctly agreeable, and since it is devoid of all stringiness it deserves to 
be widely known in America. The plant grows to a height of eight feet and 
produces an amazing amount of greens throughout the summer. _ It is as resist- 
ant to heat as New Zealand spinach and Swiss chard. 
Dr. ARNO VIEHOEVER suggests caution, however, in the use of 
this material for food. The following statement by him: was written 
after the completion of the chemical work reported in this paper. 
* From the Cattle Food and Grain Investigation enemies Bureau of Chem 
istry, United States Department of Agriculture, Washington 
2S.P.1. no. 48023. 3 Amer. Food sou January 1922. 
Botanical Gazette, vol. 74] . [158 
