284 SCIENCE OF AGRICULTURE. Part II. 



from which the hair probably derives its nourishment ; and an internal, which is membranous, and forms 

 a tube or sheath to the hair during its passage through the other layers of the skin. From this bulb, and 

 enveloped by this membrane, the hair passes through the corium, mucous web, and cuticle. It usually 

 raises up small scales of this last layer, which soon become dry and fall off, but do not form the external 

 covering of the hair, as some have supposed. The hair itself consists of an external horny covering, and 

 a central vascular part, termed medulla or pith. This horny covering consists of numerous filaments placed 

 laterally, to which different kinds of hair owe their striated appearance. These filaments appear of unequal 

 lengths, those nearest the centre being longest ; and, consequently, the hair assumes the form of an 

 elongated cone, with its base seated in the skin. This form gives to the hair that peculiar property on 

 which the operation oi felting depends. In consequence of this structure of the surface, if a hair is seized 

 at the middle between two fingers, and rubbed by them, the root will gradually recede, while the point of 

 the hair will approach the fingers ; in other words, the hair will exhibit a progressive motion in the 

 direction of the root, the imbricated surface preventing all motion in the opposite direction. It is owing 

 to this state of the surface of hairs, that woollen cloth, however soft and pliable, excites a disagreeable 

 sensation of the skin in those not accustomed to wear it. It likewise irritates sores by these asperities, and 

 excites inflammation. The surface of linen cloth, on the other hand, feels smooth, because the fibres of 

 which it consists possess none of those inequalities of surface by which hairs are characterised. 



1852. If a quantity of wool be spread upon a table, covered with a woollen cloth, and pressed down in 

 different directions, it is obvious that each hair will begin to move in the direction of its root, as if it had 

 been rubbed between the fingers. The different hairs thus moving in every direction become interwoven 

 with each other, and unite in a continuous mass. This is the felt with which hats are made. Curled 

 hairs entwine themselves with one Another more closely than those which are straight, though flexible, 

 as they do not, like these, recede from the point of pressure in a straight line; and hence hatters employ 

 various methods to produce curl in the short fur of rabbits, hares, and moles, which they employ. This 

 is accomplished chiefly by applying the solution of certain metallic salts to the fur by a brush ; so that, 

 when the hairs are dry, the surface which was moistened contracts more than the other, and produces 

 the requisite curve. 



1853. It is oiving to the asperities of the surface of hair that the spinning of wool is so difficult. This is 

 in a great measure removed, by besmearing it with oil, by which the inequahties are filled up, or, at least, 

 the asperities become less sensible. When the wool is made into cloth, it is necessary to remove the oil, 

 which is done by the process of fulling. The cloth is placed in a trough, with water and clay, and agitated 

 for some time. The oil is removed by the clay and water, while the agitation, acting like pressure, brings 

 the hairs into closer union, and the cloth is taken out, not only cleansed, but felted. The hairs of every 

 thread entwine themselves with those which are contiguous; so that the cloth may be cut without being 

 subject to ravel. It is from this tendency to felt that woollen cloth and stockings increase in density, and 

 contract in dimensions, on being washed. In many places woollen stuffs are felted, on a small scale, by 

 placing them in running water, or under cascades ; and the Zetlanders expose them to the motions of 

 the tides, in narrow inlets of the sea. 



1854. In general, there is a close connection between the colour of the hair and that of the mucous web. 

 This is displayed in those animals which are spotted, in which the colour of the skin is generally variegated 

 like that of the hair. 



1855. Hairs dlff'er remarkably inform. In general they are round. Frequently on 

 the body they are thickest in the middle. Sometimes they are flat, or two-edged ; 

 and, in the whiskers of seals, they are waved on the margins. In many animals they are 

 long and straight ; while, in others, they are crisped, and are then termed wool. When 

 stiff, they are termed bristles ; and, when inflexible, spines. 



1 856. Hair grows by the roots. In some species it is renewed annually ; and in all 

 it is readily reproduced. 



1857. Hair is the most permanent of all the substances consisting of animal matter, 

 resisting putrefaction for a great length of time. 



1858. Feathers are nearly related to hairs ; they consist of the quill, shaft, and web. 

 The quill, like the hair, takes its rise in the cellular membrane : the central portion of 

 the shaft has a texture like cork, and the web which usually occupies both sides of it is 

 composed of what are called barbes, and the sides of these with barbules. The colour of 

 feathers exhibits great difference : in some birds it varies with the seasons, in others with 

 food, and in others with the extinction of life. Like hairs, feathers are not only renewed 

 periodically, but they are readily reproduced if accidentally destroyed. 



1859. Horns take their rise from the same situation as hairs or feathers. They may 

 be regarded as hairs agglutinated, and forming a hollow cone. The fibrous structure of 

 horn may be perceived in many animals at the base, where it unites with the skin. At 

 this part it receives the additions to its growth, the apex of the cone being pushed out in 

 proportion as the increase takes place at the root, and on the inner surface. But horns 

 differ remarkably from hair, in having their central cavity filled by a projection of bone 

 or other solid substance from the body beneath. 



1860. The different markings of the horns, particularly the transverse ridges, are indications of the 

 different layers of growth ; and in many cases the number of these ridges corresponds with the years of 

 life. . ^ 



1861. The colour of the horn is, in general, distributed through the mass ; sometimes, however, it is 

 collected into bands or threads. It seldom experiences much change during the life of the animal. It is 

 permanent, or does not experience those periodical renovations which we have stated to take place with 

 hair and feathers. The deciduous horns of the stag are different in their nature from true horns, and 

 will be afterwards taken notice of The term horn is usually restricted to the coverings of the projections 

 of the frontal bones of oxen, sheep, and similar quadrupeds ; but various appendices of the skin, composed 

 of the same materials, and equally permanent, although seated on other parts of the body, may with 

 propriety be included under the same appellation ; among these may be enumerated beaks, hoofs, claws, 

 nails, and spurs. 



1862. Beaks. The substance of these covers the external surface of the maxillary 

 bones of birds, and is composed of horn. 



1863, Hoofs resemble horns in their manner of growth, and in containing a central 

 Ruppor'i, formed by the termination of the extreme bones of the feet. They grow from 



