these cells. If I examine the fibres which form the various organs of
all living animals, I should find that all of them, at one time or
other, had been formed out of a substance consisting of similar
elements; so that you see, just as we reduced the whole body in the
gross to that sort of simple expression given in Fig. 1, so we may
reduce the whole of the microscopic structural elements to a form of
even greater simplicity; just as the plan of the whole body may be so
represented in a sense (Fig. 1), so the primary structure of every
tissue may be represented by a mass of cells (Fig. 2).

Having thus, in this sort of general way, sketched to you what I may
call, perhaps, the architecture of the body of the Horse (what we term
technically its Morphology), I must now turn to another aspect. A
horse is not a mere dead structure: it is an active, living, working
machine. Hitherto we have, as it were, been looking at a steam-engine
with the fires out, and nothing in the boiler; but the body of the
living animal is a beautifully-formed active machine, and every part
has its different work to do in the working of that machine, which is
what we call its life. The Horse, if you see him after his day's work
is done, is cropping the grass in the fields, as it may be, or munching
the oats in his stable. What is he doing? His jaws are working as a
mill--and a very complex mill too--grinding the corn, or crushing the
grass to a pulp. As soon as that operation has taken place, the food
is passed down to the stomach, and there it is mixed with the chemical
fluid called the gastric juice, a substance which has the peculiar
property of making soluble and dissolving out the nutritious matter in
the grass, and leaving behind those parts which are not nutritious; so
that you have, first, the mill, then a sort of chemical digester; and
then the food, thus partially dissolved, is carried back by the
muscular contractions of the intestines into the hinder parts of the