mind, too, that I take no
account of the 30 per cent. of the so-called indigestible woody fibre
which straw contains, and which, I believe, is partly assimilable
under ordinary circumstances, and could be rendered nearly altogether
digestible by proper treatment; on the other hand, I have assumed that
the woody fibre of the oil-cake is completely digestible, although
I believe it is in reality less so than the fibre of straw.

It is an important point in the composition of oil-cakes, that they
contain a large proportion of ready-formed fatty matters which can,
with but little alteration, be at once transmuted into animal fat.
There are some individuals of the genus _Homo_ to whose stomachs fat,
_per se_, is intolerable; nevertheless, as a general rule, fatty
substances exercise a favorable influence in the process of digestion,
and, either in a separate state, or intimately commingled with other
aliments, constitute a large proportion of the food of man. Digestion in
the lower animals is, no doubt, similarly promoted by mixing with the
aliments which are to be subjected to that process, a due proportion of
oily or fatty matter. Straw is relatively deficient in the flesh-forming
principles, and abounds in the fat-forming elements--of which, however,
the most valuable, oil, is the least abundant. Now, if we add to straw
a due proportion of some substance very rich in flesh-formers and oil,
the compound will possess in nicely adjusted proportions all the
elements of nutrition. Perhaps the best kind of food which we could
employ for this purpose is linseed meal. It contains about 24 per
cent. of flesh-formers, 35 per cent. of a very bland oil, and 24 per
cent. of gum, sugar, and mucilage. Linseed-cake may be substituted for
linseed-meal; but the meal, though its cost is 15 per cent. greater, is,
I believe, rather the better article of the two. Its flesh-formers are
more soluble, and its oil thrice more abundant and far more palatable
than the same principles in most samples of oil-cake. An important
point, too, is, that linseed, unlike linseed-cake, is not liable to
adulteration. As linseed possesses laxative properties it cannot be
largely employed; the addition, however, of bean-meal--the binding
tendency of which is well known--to a diet partly composed of linseed
will neutralise, so to speak, the relaxing influence of the oily seed.
If oil-cakes be used as an adjunct to straw, rape-cake will be found
more economical th