98. FAT is dissolved by boiling; but as it is contained in cells covered
by a very fine membrane, which never dissolves, a portion of it always
adheres to the fibres. The other portion rises to the surface of the
stock, and is that which has escaped from the cells which were not
whole, or which have burst by boiling.

99. GELATINE is soluble: it is the basis and the nutritious portion of
the stock. When there is an abundance of it, it causes the stock, when
cold, to become a jelly.

100. OSMAZOME is soluble even when cold, and is that part of the meat
which gives flavour and perfume to the stock. The flesh of old animals
contains more _osmazome_ than that of young ones. Brown meats contain
more than white, and the former make the stock more fragrant. By
roasting meat, the osmazome appears to acquire higher properties; so, by
putting the remains of roast meats into your stock-pot, you obtain a
better flavour.

101. ALBUMEN is of the nature of the white of eggs; it can be dissolved
in cold or tepid water, but coagulates when it is put into water not
quite at the boiling-point. From this property in albumen, it is evident
that if the meat is put into the stock-pot when the water boils, or
after this is made to boil up quickly, the albumen, in both cases,
hardens. In the first it rises to the surface, in the second it remains
in the meat, but in both it prevents the gelatine and osmazome from
dissolving; and hence a thin and tasteless stock will be obtained. It
ought to be known, too, that the coagulation of the albumen in the meat,
always takes place, more or less, according to the size of the piece, as
the parts farthest from the surface always acquire _that degree_ of heat
which congeals it before entirely dissolving it.