362 
Journal of Agricultural Research 
Vol. I, No. 5 
indicated by the Folin-Denis method, that it seems evident that a con¬ 
siderable portion of it must be derived from compounds other than 
vanillin. 
These three compounds, benzoic acid, metaoxytoluic acid, and vanillin, 
although not related in the sense that they are readily derived from or 
transformed into one another, are related as shown by the following 
structural formulas: 
Benzoic acid. 
C;—COOH 
H —C C—H 
H—C C—H 
Nc/ 
i 
Benzoic acid is a naturally occurring product obtained from certain 
gums and balsams, wherein it exists as an ester. It is also present in 
some fruits, such as plums and cranberries, and has been found among 
the oxidation products of casein and gelatin. Its presence in soil might 
then result from the decay of plant tissues containing it or from oxida¬ 
tion of more complex compounds through the activity of microorgan¬ 
isms. The most remarkable fact in connection with its occurrence in 
the soils examined is that it was found in appreciable quantity in but 
one sample, although they were of the same general character. In the 
absence of accurate information regarding previous natural vegetation 
on these soils and other data that can be obtained only in the field, any 
attempt to explain this fact is out of place here. 
Metaoxytoluic acid, so far as known, is not a natural product, and its 
method of preparation in the laboratory does not suggest any process by 
which it might be formed in the soil from plant products or other com¬ 
pounds known to occur in soils. 
Vanillin has its chief natural source in the so-called vanilla beans, or 
seed pods, of Vanilla pompona. It has also been reported as found in 
small quantities in a number of other plants or plant products, and it 
probably is more widely distributed in the vegetable kingdom than has 
been supposed. At present there is no information indicating its forma¬ 
tion from other compounds through the agency of microorganisms, and 
the small quantity found in soils may possibly be regarded as an un¬ 
changed residue of plant debris. 
Using the maximum figures for quantities obtained in these investi¬ 
gations and calculating to the acre-foot of soil, the following approxi¬ 
mate quantities are obtained: Benzoic acid, 350 pounds; metaoxytoluic 
acid, 800 pounds; and vanillin, 40 pounds to the acre-foot. 
Metaoxytoluic acid. 
COOH 
H—C C—H 
1 1 
CH—C C—OH 
\c/ 
H 
Vanillin. 
0—COH 
H —C C—H 
h4 C—OCH 
I 
OH 
