s.

By the power of association, or by irritation, the parts already produced
continue their motions, and new ones are added by sensation, as above
mentioned; and lastly by volition, which last sensorial power is proved to
exist in the fetus in its maturer age, because it has evidently periods of
activity and of sleeping; which last is another word for a temporary
suspension of volition.

The original living filament may be conceived to possess a power of
repulsing the particles applied to certain parts of it, as well as of
embracing others, which stimulate other parts of it; as these powers exist
in different parts of the mature animal; thus the mouth of every gland
embraces the particles or fluid, which suits its appetency; and its
excretory duct repulses those particles, which are disagreeable to it.

4. Thus the outline or miniature of the new animal is produced gradually,
but in no great length of time; because the original nutritive particles
require no previous preparation by digestion, secretion, and oxygenation:
but require simply the selection and apposition, which is performed by the
living filament. Mr. Blumenbach says, that he possesses a human fetus of
only five weeks old, which is the size of a common bee, and has all the
features of the face, every finger, and every toe, complete; and in which
the organs of generation are distinctly seen. P. 76. In another fetus,
whose head was not larger than a pea, the whole of the basis of the skull
with all its depressions, apertures, and processes, were marked in the most
sharp and distinct manner, though without any ossification. Ib.

5. In some cases by the nutriment originally deposited by the mother the
filament acquires parts not exactly similar to those of the father, as in
the production of mules and mulattoes. In other cases, the deficiency of
this original nutriment causes deficiencies of the extreme parts of the
fetus, which are last formed, as the fingers, toes, lips. In other cases, a
duplicature of limbs are caused by the superabundance of this original
nutritive fluid, as in the double yolks of eggs, and the chickens from them
with four legs and four wings. But the production of other monsters, as
those with two heads, or with parts placed in wrong situations, seems to
arise from the imagination of the father being in some manner imitated by
the extreme vessels of the seminal glands; as the colours of the spots on
eggs, and the change of the colour o