sicles of the lungs, of the parts which
make up the skin and other membranes, all the details of those complex
parenchymatous organs which had confounded investigation so long, have
been lifted out of the invisible into the sight of all observers. It is
fair to mention here, that we owe a great deal to the art of minute
injection, by which we are enabled to trace the smallest vessels in the
midst of the tissues where they are distributed. This is an old artifice
of anatomists. The famous Ruysch, who died a hundred and thirty years
ago, showed that each of the viscera has its terminal vessels arranged in
its own peculiar way; the same fact which you may see illustrated in
Gerber's figures after the minute injections of Berres. I hope to show
you many specimens of this kind in the microscope, the work of English
and American hands. Professor Agassiz allows me also to make use of a
very rich collection of injected preparations sent him by Professor
Hyrtl, formerly of Prague, now of Vienna, for the proper exhibition of
which I had a number of microscopes made expressly, by Mr. Grunow, during
the past season. All this illustrates what has been done for the
elucidation of the intimate details of formation of the organs.

But the great triumph of the microscope as applied to anatomy has been in
the resolution of the organs and the tissues into their simple
constituent anatomical elements. It has taken up general anatomy where
Bichat left it. He had succeeded in reducing the structural language of
nature to syllables, if you will permit me to use so bold an image. The
microscopic observers who have come after him have analyzed these into
letters, as we may call them,--the simple elements by the combination of
which Nature spells out successively tissues, which are her syllables,
organs which are her words, systems which are her chapters, and so goes
on from the simple to the complex, until she binds up in one living whole
that wondrous volume of power and wisdom which we call the human body.

The alphabet of the organization is so short and simple, that I will risk
fatiguing your attention by repeating it, according to the plan I have
long adopted.

A. Cells, either floating, as in the blood, or fixed, like those in the
cancellated structure of bone, already referred to. Very commonly they
have undergone a change of figure, most frequently a flattening which
reduces them to scales, as in the epidermis and the epithelium.

B.