The hair of many of the smaller Mammalia shows considerable diversity of form, according to the part which we select for observation. Thus, if we take a long hair out of this Sable tippet, and examine it near the base, we sec (a) that it is very slender, transparent, and color, rless, covered with strongly marked imbrications, which are not obtuse teeth, but HAIR OF SABLE.

long, pointed, overlapping scales, about ten of which form a complete ring, or whorl, as it is called. The fibrous portion is moderately thick ; inclosing a wide pith of roundish cells, set in two rows, that allow the rays of light to be transmitted through their central parts.

As we trace the hair upwards (b), by moving the stage of the microscope, by-and-by it swells and rapidly increases in thickness ; the imbrications are scarcely perceptible ; while the pith-cells have greatly augmented in number and in breadth. These are arranged in confused close set, transverse rows, and are nearly opaque.

Still tracing up the same hair, as we approach the tip, the bark and fibrous part become very thin ; the cells are fewer and fewer till thev cease altogether, and a lom>slender point, of a clear yellow tinge, without cells, presents tranverse wavy lines of imbrication scarcely proiecting,

The hair of the common Alouse is a pretty and interesting object. In the larger specimens the fibrous portion is reduced almost to nothing. The imbrications project very little, but careful observation reveals slanting; lines proceeding from the "teeth;" which show that the whole surface is clothed with large pointed scales, which are very thin, and lie close. The pith consists of large flattened cells, arranged thus : one row passes up through the centre, and other similar ones are set in a

HAIR OF MOUSE. circle around it, so that a longitudinal section would show threeparallei rows. These cells are translucent, and some of them

are either wholly or partially lined with a clear yellow pigment, or colouring- matter. The smaller hairs from the same little animal

are scarcely distinguishable from those of the Cat,

already described, except that the imbrications are

proportionally larger. In all, the extremity is

drawn out to a lengthened fine point, and is occupied with clear yellow cells, except the very tip,

which is colourless, and imbricated with sinuous

whorls, each consisting of a single scale. But it is in the Bats that the imbricated

character attains its greatest development.

On this slide is a number of hairs from the

fur of one of our English Bats, in which it is

far more conspicuous than in any example

we have yet seen. In the middle portion of

each hair the scales lie close, embracing their

successors to the very edges, or nearly : but

the lower part, which is more slender, resembles a multitude of trumpet-shaped flowers

formed into a chain, each being inserted into

the throat of another. The lip of the "flower''

is generally oblique, and here and there we

can perceive that each is formed of two halfencircling scales ; for one scale occasionally mouse, springs from the level of its fellow, so as to " A bat. make the imbrication alternate.

Even this, however, is far excelled by a species of Bat from India, of whose hair I have now specimens on the stage. The trumpet-like cups are here very thin and transparent, but very expansive ; the diameter of the lip being, in some parts of the hair, fully thrice as great as that of the stem itself. The margin of each cup appears to be undivided, but very irregularly notched and cut. In the middle portion of the hair, the cups are far more crowded than in the basal part, more brush-like, and less

elegant ; and this structure is continued to the very extremity, which is not drawn out to so attenuated a point as the hair of the Mouse, though it is of a needle-like sharpness. The trumpet-shaped scales are, it seems, liable to be removed by accident; for in these dozen hairs there are several in which we see one or more cups rubbed off, and in one the stem is destitute of them for a considerable space. The stem so denuded closely resembles the basal part of a Mouse's hair in its ordinary condition. This character of being clothed witli overlapping scales, each growing out of its predecessor, is common, then, to the hairs of the Mammalia, though it exists in different degrees of development. It may be readily detected by the unaided HAIR OF INDIAN BAT. sense, even when the eye, though assisted by the microscope, fails to recognise it. Almost every schoolboy is familiar with the mode by which the tip of any hair may be distinguished from its base ; and, even of the least fragment, the terminal end from the basal end. A hair is rubbed to and fro between the finger and thumb, and it regularly travels through in the direction of its base ; thus enabling the boy after one or two rubs to pronounce a very decided opinion on the subject. Now you see the cause of this property lies in the imbricate structure ; the scales may be ever so thin and close, but still they project sufficiently in any specimen to present a barrier to motion in the direction of the tip when pressed between two surfaces, such as the fingers, while they very readily move in the oppc site.

But more than the success of a schoolboy's magic depends on the imbricate surface of hairs. England's timehonoured manufacture, that which affords the highest

seat in her most august assembly, depends on it. The hat on your head, the coat on your back, the flannel waistcoat that shields your chest, the double hose that comfort your ankles, the carpet under your feet, and hundreds of other necessaries of life, are what they are, because mammalian hairs are covered with sheathing scales.

It is owin£ to this structure that those hairs which possess it in an appreciable degree are endowed with the property of felting ; that is, of being, especially under the combined action of heat, moisture, motion, and pressure, so interlaced and entangled as to become inseparable; and of gradually forming a dense and cloth-like texture. The " body " or substance of the best sort of men's hats is made of lamb's wool and rabbit's fur, not interwoven, but simply beaten, pressed, and worked together, between damp cloths. The same property enables woven woollen tissues to become close and thick ; every one knows that worsted stockings shrink in their dimensions, but become much thicker and firmer, after they have been worn and washed a little ; and the " stout broad-cloth," which has been the characteristic covering of Englishmen for ages, would be but a poor, open, flimsy texture, but for the intimate union of the felted wool fibres, which accrues from the various processes to which the fabric has been subjected.

In a commercial view, the excellence of wool is tested by the closeness of its imbrications. When first the woolfibre was submitted to microscopical examination, the experiment was made on a specimen of Merino; it presented 2,400 little teeth in an inch. Then a fibre of Saxon wool, finer than the former, and known to possess a superior felting power, was tried: there were 2,720 teeth in an inch. Next a specimen of South-Down wool, acknowledged to be inferior to either of the former, was examined, and gave 2,080 teeth. Finally, the Leicester wool, whose felting property is feebler still, yielded only 1,850 teeth per inch. And this connection of good felting quality with the number and sharpness of the sheathing scales, is found to be invariable.

The hairs of many insects are curious and interesting. Here you may see the head of the hive bee, which is moderately clothed with hair ; each hair is slender and pointed, and is beset with a multitude of other short hairs, which project from the main stem, and stand out at an angle : these are set on in a spiral order. Here, again, is one of the hinder legs of the same bee : the yellow hair, which you can see with the naked eye, consists of strong, horny, curved spines, each of which is scored obliquely, like a butcher's steel. These legs are used, as you are well aware, to brush off the pollen from the anthers of flowers, wherewith the substance called beebread, the food of the grubs, is made : and in this specimen, you may see hundreds of the beautiful oval pollen-grains entangled among these formidable-looking spines. These rusty hairs are from a large caterpillar (that of the Oak Egger Moth, I believe) ; they appear, when highly magnified, like stout horny rods drawn out to a sharp point, and sending forth alternate short pointed spines, which scarcely project from the line of the axis. But there is scarcely any hair more curious than that of a troublesome grub in museums and cabinets, the larva of Dermestes lardarius, which lives upon fur-skins, and any dried TIP OF HAIR OF animal substances. It has a cylindrical shaft, DEBMESTES. which is covered with whorls of large close-set spines, four or five in each whorl, closely succeeding each other; the upper part of the shaft is surrounded by a whorl of larger and more knotted spines, and the extremity

is furnished with six or seven large filaments or threads, which appear to have a knob-like hinge in the middle, by which they are bent up on themselves.

The feathers of Birds are essentially hairs. That shrivelled membrane which we pull out of the interior of a quill when we make a pen, is the medullary portion, dried. There is a beautiful contrivance in the barbs, or beards, of most feathers, which I will illustrate by this feather from the body-plumage of the domestic fowl. Every one must have observed the regular arrangement of the vane of a feather, and the exquisite manner in which the beards of which it is composed are connected together. This is especially observable in the wing-feathers—a goose-quill for example, L^. where the vane, though very light and thin, forms an exceedingly firm resisting medium, the individual beards maintaining their union with great tenacity, and resuming it immediately, when they have been violently separated.

]N~ow this property is of high importance in the economy of the EAEB 0F ™;™L G FE^THEE bird. It is essential that with great lightness and buoyancy—for the bird is a flying creature—there be power to strike the air with a broad resisting surface. The wide vanes of the quill-feathers afford these two requisites, strength and lightness ; the latter depending on the material employed, which is very cellular, and the former on the mode in which the individual barbs, set edgewise to the direction of the stroke, take a firm hold on each other.

jSTow, in the bodv-feather, which is under the micro-

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