358 
Journal of Agricultural Research 
Vol. I, No. 5 
colored extract siphoned off. This extract was acidified with sulphuric 
acid, filtered, and the acid filtrate shaken out several times with ether. 
The ether extracts were combined and the ether evaporated on the sur¬ 
face of a small quantity of warm water. The water was then heated to 
boiling and filtered hot, when, on cooling the filtrate, crystals separated. 
A further yield of crystals was obtained on concentrating the mother 
liquor from the crystals first obtained. The compound obtained in this 
way was purified by recrystallizing from water, and finally by sublima¬ 
tion, when a pure white product was obtained. About 2 grams were 
obtained from 25 kilograms of soil. 
This compound had all the properties of benzoic acid. It crystallized 
in the leaflets characteristic of benzoic acid. It was readily soluble in 
alcohol, ether, and chloroform, sparingly soluble in cold water but much 
more readily in hot water, and melted at 121° C. An aqueous solution 
was acid in reaction, and when neutralized and treated with a neutral 
solution of ferric chlorid a dirty-brown precipitate was formed that was 
insoluble in acetic acid. The compound sublimed readily and when 
heated strongly gave off the irritating fumes characteristic of benzoic acid 
when so treated. Finally it gave Mohler’s reaction. 1 
The appearance and properties of the compound obtained from the 
soil, its behavior with ferric chlorid, and response to Mohler’s test are 
sufficient to establish its identity as benzoic acid. 
METAOXYTODUIC ACID 
Metaoxytoluic acid was obtained from several samples of the series 
examined, but in quantity only from subsoils. The method by which it 
was obtained was exactly the same as that just outlined for benzoic add 
up to the point of obtaining a water solution of the ether extract. If no 
benzoic add or other compound separated on cooling the filtrate, it was 
concentrated nearly to dryness and allowed to stand, when oxytoluic add, 
if present, crystallized out. The compound so obtained was purified by 
repeated recrystallizations from water and was finally dried on a porous 
plate. This product retained persistently a slight tinge of color, and it 
was only after many treatments and much loss of material that it could 
be freed from color. Where traces of benzoic add accompanied it, as 
seemed to be the case in some instances, it could be freed from benzoic 
add by sublimation, this acid being much more readily sublimed than 
oxytoluic add. About 10 grams of pure material were obtained from 25 
kilograms of soil. 
1 Mohler’s test is carried out by heating the substance to be determined with sulphuric add until charring 
takes place, sulphobenzoic acid being formed if benzoic acid is present in the original material. On-treat¬ 
ing with potassium nitrate this "will be transformed into metadinitro-benzoic acid. On adding excess of 
ammonia to this add and then a few drops of a colorless solution of ammonium sulphid a red color will 
be obtained. 
Offidal and provisional methods of analysis, Association of Official Agricultural Ch emis ts. U. S. Dept. 
Agr. Bur. Chem. Bui. 107 (rev.), p. 181, 1908. 
Mohler, E. Recherche de l'adde benzoique dans les substances alimentaires. Bui. Soc. Chim., Paris, 
s. 3, t. 3, p. 414-416, 1890. 
