Note on the Behaviour of Hippuric Acid in Soils, 
BY 
K. Yoshimura, Nögakushi. 
The manurial effect of urine stands among other things in a 
certain ratio to its amount of nitrogenous compounds, and to 
the readiness with which these are converted into ammonia. 
Kellner has shown that urea as such is not absorbed by 
the soil and that surface soil more readily converts it into am¬ 
monium carbonate than soil from a certain depth. Uric acid 
can also readily undergo fermentation, with the production of 
ammonia and carbon dioxide, and with simultaneous oxidation. (1) 
C 5 H 4 N 4 0 3 T8H 2 0 + 30 = 4 NH 3 + 5C0 2 +4H 2 0. 
But there exists a considerable amount of nitrogen in still 
another form in the urine of cattle and horses, viz., as hippuric 
acid. 
.About io % of the total nitrogen of cattle-urine and about 
2 % of that of horse-urine are present in this form. As hippuric 
acid evidently resists the fermentative action of microbes more 
than urea or uric acid, it seemed to me of interest to observe the 
behaviour of hippuric acid in soils. 
At first, however, I tested soil in regard to its absorptive 
power for this compound. 
It seemed to me possible that soil rich in hydrated oxide of 
iron might show some absorptive power, ferric hippurate being 
insoluble. Two kinds of soils were tested ; one, from the farm 
of this College in Komaba, near Tokyo, consists of volcanic 
ashes and loam, and contains about 8 % of humus and 8-n % 
of oxide of iron ; it has a high absorptive power for ammonia 
and phosphoric acid. The 'other, from Tochigi, is of clayey 
nature ; both soils are almost free from calcium carbonate. 
( i) Sestini. Landw. Vers. Stat., 38., 157. 
