186 
Solubility of Phosphatic Materials, 
The hard texture of these three samples, more especially that 
of the first, obviously resisted the solution of the bone-phosphate 
in water — a result agreeing well with that obtained in experi- 
ments already cited. 
Cold water in contact with bone-dust, it will be noticed, 
extracts an appreciable quantity of nitrogenous organic matter, 
more being present in the first than in the subsequent extracts. 
The presence of a comparatively small quantity of soluble 
organic matter, however, does not appear in these experiments to 
have increased the solubility of phosphate of lime ; for whilst the 
proportion of nitrogen present in the shape of organic matter was 
much greater in the first than in the second or third solution, 
the amount of phosphate of lime remained, practically speaking, 
the same in each set of experiments. 
Experiments with Spongy Half-inch Bone. 
A sample of commercial bone-dust, made entirely from porous 
spongy bones and boiled in an open copper, so as to extract 
most of the grease, but not to act sensibly upon the gelatine of 
the bone, was next experimented upon in the same manner as in 
the preceding instances. The results stated per gallon are given 
in the subjoined Table : — 
Amount of Bone-phosphate and of Nitrogen dissolved hy 1 gallmi of Water 
from spongy half-inch Bone digested for 24 hours in cold water, in the 
proportion of 500 grains to 1 decigallon of Water. 
Bone-phosphate. Nitrogen. = Ammonia. 
Grains. Grains. Grains. 
Spongy 2-inch bone | 
let gallon of water 5-61 .... 27-30 = 33-15 
2nd „ 2-45 .... 4-35 5-28 
The results of this experiment show plainly that the nitrogen- 
ous constituents and bone-phosphates are more easily dissolved 
from porous though very coarse bone-dust than from fine dust 
made from solid bone. 
A portion of the nitrogen found in the first watery solution 
of the spongy bone was present in the state of an ammoniacal 
salt, for the bone-dust moistened with water on the addition of 
soda-lime, liberated free ammonia, which was readily perceptible 
by its characteristic pungent smell. The presence of an am- 
monia salt accounts for the much larger proportion of bone- 
phosphate in the first solution ; for direct experiments with 
bone phosphate of lime and weak solutions of ammonia salt, as 
pointed out above, show that the latter exercise a decidedly solvent 
action upon bone phosphates. 
Ammoniacal salts, being very soluble in water, cannot occur 
in any appreciable quantity in the second watery extract of the 
