50 
Action and Practical Application of Bones 
The necessity for the inquiry is not the less evident. Thus, 
as regards the theory of the action of the manure, our highest 
authorities only agree on one point to differ on another ; and the 
part each constituent of the bone plays in the soil is yet a qucestio 
vexata. 
On the first use of bone-manure it was imagined that its animal 
oil and gelatine* were the sole fertilizing ingredients it contained. 
And this was held on the well-grounded fact that such animal 
matters, if applied alone, have a powerful effect upon vegetation. 
However true this might be, it did not authorize such a conclu- 
sion ; and the accidental use of bones which had been so long 
exposed to the action of the atmosphere that they had lost their 
animal oil, threw grave doubts upon the theory. At this stage 
opinion halted. Bones, however, which had lost a portion of their 
organic matter by combustion, whether arising from natural decom- 
position or from the application of artificial heat in the various 
processes of certain manufactures, came gradually into use and 
favour. In a few years, indeed, the boiled bones of commerce 
(from which the fat and a large portion of the gelatine had been 
extracted) were bought in preference to those which still contained 
the whole of their animal matter. This preference still continues, 
and has tended to countenance the opposite theory to the one 
originally held. This theory is that the inorganic constituents of 
bones are the sole manuring substances that have effect upon the 
crop. As the champion of this theory, Sprengel has instanced 
the results of his experiments with bones from which the whole 
of the organic part had been burnt away. These experiments 
show that the bones had lost in no degree their power of fertilizing. 
As confirmatory of these trials, experiments made by the writer 
during the last few years have been instanced,! and so far as 
regards the fact asserted by Sprengel, that bones burnt, so as to 
lose their animal matter, act equally well with those which still 
contain it, tliese experiments certainly do not contradict, but in a 
degree confirm it, — the burnt bones in one instance acting better 
than the fresh ones, and in another worse. At the same time, 
* It may be well to observe here that bones may be divided into two 
parts — an organic part which will burn away, and an inorganic part which 
will not burn away. The organic part consists oifat, gelatine, and water, 
and the inorganic principally phosphate of lime. 
The following may be stated as an average of the proportions of each 
of these constituents in 100 parts of 
Animal matter 1 Oil , . . \nr.t. 
and Water { Gelatine . . }20 to 45 parts. 
I Phosphate of lime, 70 to 40 parts. 
Earthy matter J Other salts of lime, 1 1„ . ,j, . 
I .„o.v„,. flO to 15 parts. 
I magnesia, ccc. ) ' 
t Ry Mr. Pusey. Royal Agr. Journal, vol. iv. p. 408. 
