7. There were present, also, numerous tesselated
epithelial cells.

That is, the cells of the mucous membrane
(called epithelial cells) were tesselated, or
disposed like the stones of a pavement, which
proved that they came from the lining of the
throat. For the mucous membrane lining the
throat is composed of tesselated cells; that
covering the root of the tongue of columnar
cells, or cells arranged in tall cones or cylinders;
and that lining the viscera is ciliated, or carrying
small waving hairs at the tips. Thus, the
microscope revealed beyond doubt that this
knife had cut the throat of a living human body,
which throat had been protected by a certain
cotton fabric. The evidence tallied so exactly
with the actual and supposed condition of things,
that it was held to be conclusive, and the
murderer was hung. Without the microscope
he might have escaped punishment altogether.

The human hair is a singularly beautiful thing
to look at under the microscope. It is made of
successive layers, or overlapping cells, gradually
tapering to a point like the thinnest and most
infinitely twisted paper cone. The edges are
serrated with shallow saw-like teeth; it is
perfectly translucent, and marked with a great
many transverse lines, exceedingly irregular and
sinuous. Hogs' bristles are more like human
hairs than any other animal's; but the sinuous
lines are finer and closer, and no saw-teeth are
visible at the edges. The finer hair of the horse
and ass have the overlapping plates about as
close as in the human hair, but they are strikingly
different in the arrangement of the medulla
or pith.

We must go wool-gathering (literally, not
metaphorically) with Mr. Gosse and his
delightful book entitled Evenings with the
Microscope, to which we are indebted for the greater
part of this paper. "Sheep's wool," he says,
"is clothed with imbrications proportionally
much fewer than those of human hair:"
that is, the layers or rolls of our twisted paper
cone are pulled farther out, which makes them
wider apart, at the same time that the cone
itself is much attenuated. These imbrications
are of infinite importance; for on them
depends the felting quality of wool, by which
we are enabled to have flannel and broadcloth,
carpets for our houses, stockings for our feet,
soft stuff for ladies' dresses, thick duffel for old
women's petticoats, window hangings, and
blankets, scouring flannel, and cashmere shawls.
The more imbrications to the inch in the woollen
fibre, the better, closer, and stouter the material
made. In the first microscopical examinations,
a fibre of merino was found to have ten thousand
four hundred serratures to the inch; a fibre of
Saxon wool, which is finer and possessed of a
superior felting power, had two thousand seven
hundred and twenty; Southdown, inferior to
both, gave two thousand and eighty; and
Leicestershire wool, notoriously inferior to all,
had only one thousand eight hundred and fifty.

The prettiest hair of all is the bat's. It is like
an immense number of trumpet-shaped flowers
set one within the other—a living chain of
expanded bells, most beautiful to behold. The
hair of the Indian bat is even more flower-like
and elegant than that of its English cousin, as
the lips of the "flowers" are closer together,
more pointed, and more feathery in the growth.
It is to the English bat's what a double flower
is to a single, or a garden flower to a wild
one.

Hive bees have slender pointed hairs upon the
head, each hair beset with a number of
subordinate short hairs set on in spirals: on the
leg, the yellow hairs which we can see with the
naked eye, turn out to be strong curved horny
spines, scored obliquely like a butcher's steel,
and used as combs for gathering, storing, and
scraping out the pollen. Besides his combs,
the bee carries two baskets in his thighs, which
baskets are the perfection of such implements,
being smooth inside, of undeniable form, and
staked up with strong spines: in short, the very
ideal of such baskets we should use for carrying
pollen or flower grain. But this is, by-the-by,
out of our present line. Birds' feathers are
essentially hairs, of a highly complex arrangement,
and not much like hairs in outward
appearance, but in use and analogy nothing
more nor less. Each barbule of the vane is
composed of a series of secondary barbulets, all
of which lock, or rather hook-and-eye together,
in the strongest form of union known. This is
the reason why the vane is so difficult to separate,
and why it springs back with such force
when torn asunder for a moment. The whole
vane is composed of these barbs and barbules,
one side of which is furnished with hooks, the
other with loops, and so they lock together with
a strength which nothing but great violence can
overcome.

From hair to scales is but a step; for scales
are fishes' hairs, as feathers are birds' hairs, and
all three answer the same purposes in animal
economy. The scales of a fish overlap each
other like the tiles of a house, so that the water
always runs from them, and cannot by any
possibility runup in between; just as air and water
cannot run upward through a bird's plumage,
but must flow off and downward. Different fish
have differently shaped scales. The scales of
the perch have their free sides set with fine
crystalline points, arranged in successive rows,
and overlapping; gold and silver fish have no
crystalline points on their free edges, but lining
each scale is a layer of soft pigment, a
bright gleaming substance, golden or silvery,
according to the colour of the fish. This
pigment divides again into two substances, one of
which gives colour and the other metallic lustre.
The former is simply a layer of loose membranous
cells, orange-coloured or white, as the
case may be; the latter are flat specula or
crystals, oblong prisms with angular edges.
These crystals are quite transparent, and scarcely
visible at all, when seen by transmitted light; by
reflected light they give back a glancing shine,
like steel plates.  They are always quivering,
flashing, vibrating, and perhaps are the cause of