ilar in their composition to the bones of
quadrupeds.

_The Organic Matter of Bones._

The organic portion of bones is almost entirely made up of a substance
to which the name _ossein_ has been given, and which, when boiled for a
long time, is converted into gelatine. This ossein, which forms on an
average from 25 to 30 per cent of the weight of bones, is extremely rich
in nitrogen, containing over 18 per cent.

_Inorganic Portion of Bones._

The inorganic portion, which forms about 70 per cent, is made up chiefly
of phosphate of lime. The dry leg-bones of oxen and sheep, according to
Heintz, have the following percentage composition:--

Per cent.
Phosphate of lime 58 to 63
Carbonate of lime 6 to 7
Phosphate of magnesia 1 to 2
Fluoride of calcium 2
Organic matter 25 to 30

According to Payen and Boussingault, raw bones contain 6-1/4 per cent of
nitrogen and 8 per cent of water. Pure bones are thus seen to contain
about 29 per cent of phosphoric acid and 6-1/4 per cent of nitrogen. The
composition of the commercial article, however, differs very widely.
This is due to the fact that bones collected from India and America,
where they have been long exposed to atmospheric influences, have lost
much of their organic matter. The amount of sand and earthy impurities
also varies very considerably.

_Treatment of Bones._

Bones are used for the manufacture of glue and gelatine. These are
extracted from them by steaming the bones. The bones after treatment are
used as a manure. The improvement noted in the action of the bones thus
treated led to the introduction of the use of steamed bones as a manure.
Raw bones are now rarely used. The fat present in raw bones retards
their decomposition in the soil. Probably, as has been suggested, it
forms along with lime an insoluble soap which prevents the mineral
matter in the bone being dissolved by the carbonic acid of the soil. In
the process of boiling or steaming a certain loss of nitrogen takes
place, greater or less, according to the length of time they are boiled
or steamed, and in the latter case the pressure applied. A more
economical method for extracting the fat has been introduced by using
benzine, but this process is not used to any extent. The loss of
nitrogen in the former case is more than compensated for by their more
speedy action as a manu