THE NITROGENOUS PRINCIPLES OF URINE, 297 
Washed and ignited flower-pots were employed, to con- 
tain, for each trial, a soil consisting of 700 grms. of 
ignited and washed granitic sand, mixed with 0.25 grm, 
sulphate of lime, 2 grms. ashes of hay, prepared in a muffle, 
and 2.75 grms. bone-ashes. This soil was placed upon 
100 grms. of clean gravel to serve as drainage. 
In each of four pots containing the above soil was de- 
posited, July 6th, a weighed kernel of maize. The pots 
were watered with equal quantities of distilled water con- 
taining a scarcely appreciable trace of ammonia. The 
seeds germinated in a healthy manner, the plants devel- 
oped slowly and alike until July 28th, when the addition 
of nitrogenous matters was begun. 
To No. 1, no solid addition was made. 
To No. 2 was added, July 28th, 0.420 grm. uric acid. 
To No. 8 was added 1.790 grm. hippuric acid, at four 
different times, viz: July 28, 0.358 grm., Aug. 26th, 0.358 
grm., Sept. 16th, 0.716 grm., Oct. 3d, 0.3858 grm. 
To No. 4was added 0.4110 grm. hydrochlorate of gua- 
nine, viz: July 28th, 0.0822 grm., Aug. 26th, 0.0822 
grm., Sept. 16th, 0.1644 grm., Oct. 3d, 0.0822 grm. 
The nitrogenous additions contained in each case, 0.140 
erm. of nitrogen, and were strewn, as fine powder, over 
the surface of the soil, 
The plants continued to grow or to remain healthy (the 
lower leaves withering more or less) until they were re- 
moved from the soil, Nov. 8th, 
The plants exhibited striking differences in their devel- 
opment.. No. 1 (noadded nitrogen) produced in all seven 
slender leaves, and attained a height of 7 inches. At the 
close of the experiment, only the two newest leaves were 
perfectly fresh ; the next was withered and dead through- 
out one-third of its length. The newer portions of this 
plant grew chiefly at the expense of the older parts. No 
sign of floral organs appeared. 
13* 
