hout the one hampering the other, she does so, instead of
acting like a coppersmith who for cheapness makes a spit and
lampholder in one" (iv., 6, 683^a).

(5) The first sentence of the _Historia Animalium_ formulates, with
that simplicity and directness which is so characteristic of
Aristotle, the distinction between homogeneous and heterogeneous
parts, in the mass the distinction between tissues and organs. "Some
parts of animals are simple, and these can be divided into like parts,
as flesh into pieces of flesh; others are compound, and cannot be
divided into like parts, as the hand cannot be divided into hands, nor
the face into faces. All the compound parts also are made up of simple
parts--the hand, for example, of flesh and sinew and bone" (Cresswell,
_loc. cit_., p. I).

In the _De Partibus Animalium_ he broadens the conception by adding
another form of composition. "Now there are," he says, "three degrees
of composition; and of these the first in order, as all will allow, is
composition out of what some call the elements, such as earth, air,
water, fire.... The second degree of composition is that by which the
homogeneous parts of animals, such as bone, flesh, and the like, are
constituted out of the primary substances. The third and last stage is
the composition which forms the heterogeneous parts, such as face,
hand, and the rest" (ii., 1, 646^a, trans. Ogle).

In the _Historia Animalium_ the homogeneous parts are divided into (1)
the soft and moist (or fluid), such as blood, serum, flesh, fat, suet,
marrow, semen, gall, milk, phlegm, faeces and urine, and (2) the hard
and dry (or solid), such as sinew, vein, hair, bone, cartilage, nail,
and horn. It would appear from this enumeration that Aristotle's
distinction of simple and complex parts does not altogether coincide
with our distinction of tissues and organs. We should not call vein a
tissue, nor do we include under this heading non-living secretions.
But in the _De Partibus Animalium_ Aristotle, while still holding to
the distinction set forth above, is alive to the fact that his simple
parts include several different sorts of substances. He distinguishes
among the homogeneous parts three sets. The first of these comprises
the tissues out of which the heterogeneous parts are constructed,
_e.g._, flesh and bone; the second set form the nutriment of the
parts, and are invariably fluid; while the third set are the residue
of the second and constitute the