ously existing, and to which the new parts are to be attached.

3. In confirmation of these ideas it may be observed, that all the parts of
the body endeavour to grow, or to make additional parts to themselves
throughout our lives; but are restrained by the parts immediately
containing them; thus, if the skin be taken away, the fleshy parts beneath
soon shoot out new granulations, called by the vulgar proud flesh. If the
periosteum be removed, a similar growth commences from the bone. Now in the
case of the imperfect embryon, the containing or confining parts are not
yet supposed to be formed, and hence there is nothing to restrain its
growth.

4. By the parts of the embryon being thus produced by new apportions, many
phenomena both of animal and vegetable productions receive an easier
explanation; such as that many fetuses are deficient at the extremities, as
in a finger or a toe, or in the end of the tongue, or in what is called a
hare-lip with deficiency of the palate. For if there should be a deficiency
in the quantity of the first nutritive particles laid up in the egg for the
reception of the first living filament, the extreme parts, as being last
formed, must shew this deficiency by their being imperfect.

This idea of the growth of the embryon accords also with the production of
some monstrous births, which consist of a duplicature of the limbs, as
chickens with four legs; which could not occur, if the fetus was formed by
the distention of an original stamen, or miniature. For if there should be
a superfluity of the first nutritive particles laid up in the egg for the
first living filament; it is easy to conceive, that a duplicature of some
parts may be formed. And that such superfluous nourishment sometimes
exists, is evinced by the double yolks in some eggs, which I suppose were
thus formed previous to their impregnation by the exuberant nutriment of
the hen.

This idea is confirmed by the analogy of the monsters in the vegetable
world also; in which a duplicate or triplicate production of various parts
of the flower is observable, as a triple nectary in some columbines, and a
triple petal in some primroses; and which are supposed to be produced by
abundant nourishment.

5. If the embryon be received into a fluid, whose stimulus is different in
some degree from the natural, as in the production of mule-animals, the new
irritabilities or sensibilities acquired by the increasing or growing
organized parts ma