electricity; and the same sort of argument which demonstrates the two
latter to be related to one another shows that the nervous forces are
correlated to electricity; for the experiments of M. Dubois Reymond and
others have shown that whenever a nerve is in a state of excitement,
sending a message to the muscles or conveying an impression to the
brain, there is a disturbance of the electrical condition of that nerve
which does not exist at other times; and there are a number of other
facts and phenomena of that sort; so that we come to the broad
conclusion that not only as to living matter itself, but as to the
forces that matter exerts, there is a close relationship between the
organic and the inorganic world--the difference between them arising
from the diverse combination and disposition of identical forces, and
not from any primary diversity, so far as we can see.

I said just now that the Horse eventually died and became converted
into the same inorganic substances from whence all but an inappreciable
fraction of its substance demonstrably originated, so that the actual
wanderings of matter are as remarkable as the transmigrations of the
soul fabled by Indian tradition. But before death has occurred, in the
one sex or the other, and in fact in both, certain products or parts of
the organism have been set free, certain parts of the organisms of the
two sexes have come into contact with one another, and from that
conjunction, from that union which then takes place, there results the
formation of a new being. At stated times the mare, from a particular
part of the interior of her body, called the ovary, gets rid of a
minute particle of matter comparable in all essential respects with
that which we called a cell a little while since, which cell contains a
kind of nucleus in its centre, surrounded by a clear space and by a
viscid mass of protein substance (Fig. 2); and though it is different
in appearance from the eggs which we are mostly acquainted with, it is