s at the same time cleared up
many uncertainties concerning the mechanism of the special functions. Up
to the time of the living generation of observers, Nature had kept over
all her inner workshops the forbidding inscription, No Admittance! If
any prying observer ventured to spy through his magnifying tubes into the
mysteries of her glands and canals and fluids, she covered up her work in
blinding mists and bewildering halos, as the deities of old concealed
their favored heroes in the moment of danger.

Science has at length sifted the turbid light of her lenses, and blanched
their delusive rainbows.

Anatomy studies the organism in space. Physiology studies it also in
time. After the study of form and composition follows close that of
action, and this leads us along back to the first moment of the germ, and
forward to the resolution of the living frame into its lifeless elements.
In this way Anatomy, or rather that branch of it which we call Histology,
has become inseparably blended with the study of function. The
connection between the science of life and that of intimate structure on
the one hand, and composition on the other, is illustrated in the titles
of two recent works of remarkable excellence,--"the Physiological
Anatomy" of Todd and Bowman, and the "Physiological Chemistry" of
Lehmann.

Let me briefly recapitulate a few of our acquisitions in Physiology, due
in large measure to our new instruments and methods of research, and at
the same time indicate the limits which form the permanent or the
temporary boundaries of our knowledge. I will begin with the largest
fact and with the most absolute and universally encountered limitation.

The "largest truth in Physiology" Mr. Paget considers to be "the
development of ova through multiplication and division of their cells."
I would state it more broadly as the agency of the cell in all living
processes. It seems at present necessary to abandon the original idea of
Schwann, that we can observe the building up of a cell from the simple
granules of a blastema, or formative fluid. The evidence points rather
towards the axiom, Omnis cellula a cellula; that is, the germ of a new
cell is always derived from a preexisting cell. The doctrine of Schwann,
as I remarked long ago (1844), runs parallel with the nebular theory in
astronomy, and they may yet stand or fall together.

As we have seen Nature anticipating the plasterer in fibro-cartilage, so
we see her beforehand