THE MAMMALIA—MAN AND BEASTS. 
91 
rated from it. Caustic alkalis and some acids dissolve it entirely. Sulphur, silica, 
iron, and manganese, may be traced in the hair. 
There are certain prolongations of a horny substance, which grow upon the heads 
of some species of iSIammalia, especially the Rumiuantia. These also appear on 
several other parts of animals. 
The term Horn, as applied in the arts, would exclude the excrescences of the Stag, 
Deer, Rein-deer, Elk, and others, which consist rather of a bony substance, distin- 
guished by the term antler. The horns of this division of Ruminants are true hones, 
and composed like them of a cartilaginous matter, within the meshes of which, par- 
ticles of phosphate of lime are deposited, constituting a kind of earthy salt, commonly 
known as earth of bones or hartshorn. 
These antlers, in their perfect state, are true bones both in their texture and ele- 
ments, the external part b.^ing hard, compact, and Hbrous; the internal spongy, but 
very solid. There are no largo cells, medullary cavities, or sinuses. The bases of 
these antlers adlierc to the frontal bone, forming one body with it, in such a way as 
to render it impossible to point out, at certain ages, the limits between them. I he 
skin which covers the forehead does not extend farther. It is surrounded by a den- 
ticulated bony substance, called the Neithor skin nor periosteum covers tins 
substance or the rest of the antler. Furrows more or less deep, which are the ves- 
tiges of vessels distributed along their surfaces while they were yet soft, are alone 
to bo traced on the exterior. These hard and naked horns remain only for one year 
on the head of the Stag. The period of their fall is varied according to tlio species ; 
but when near, there appears, on sawing them longitudinally, a reddish mark of 
separation between them ami the supporting eminence of the frontal bone. This 
mark becomes gradually more apparent, and the bony particles at length lose their 
adhesion at that part. A very slight shock then makes the antlers drop off at that 
period, and two or three days commonly intervene between the fall of the one antler 
and that of the other. 
The eminence of the frontal bone resembles, at that time, a bone broken or sawed 
through transversely, and its spongy texture is exposed. The skin of the forehead 
soon, however, covers it ; and when the horns are again about to shoot, tubercles 
arise, which remain covered by a production of the same skin until their perfect size 
has been attained. During the whole of this operation, the tubercles are soft and 
cartilaginous. Under the skin a true periosteum is found, in which vessels, some- 
times of great size, are distributed, and penetrate the mass of cartilage in every 
direction. The cartilage ossifies gradually, and, passing through the same stages 
as the bones of the foetus, ends in becoming a peifect bone. During this time, 
the burr at the ba.se of the horn ponetrate.s the indentations through which the 
vessels pass, and also develops itself. The indeiUations by their growth confine the 
vessels, and finally ohslruct them. Then the skin and periosteum of the bones wither, 
die, and fall off. The bones, now become bare, in a short time fall off, only to be 
renewed by others, but always of a larger size than the first. 1 he antlers of the 
■"^tag arc subject to diseases e(iually with other bones, and of the same kind. In 
some the calcareous matter is extravasated, and forms different exostoses ; in others, 
on the contrary, it is found in too small a quantity, and the bones continue porous, 
light, and without consistence. 
The true horns, such as those of the Bull, Ram, Goal, and Chamoi-s, are formed 
npon processes of bone, and differ materially from antlers in this respect, that they 
grow at their root or base, and bear a grc.it analogy to the other integuments. 
This view is established by investigating the manner in which the horns of the 
Calf exhibit themselves. In the third month of conception, while the foetus of the 
Cow is still inclosed in the membrane, the cartilaginous frontal bone pieseiitsno 
mark of the horns which it aft'Twards bears. It becomes partly ossified towards tbo 
seventh motilh, and presents in its two portions the small tubercle, which appears to 
he produced by the elevation of the osseous laminae. These bony tumours soon after 
appear externally, and raise the skin in proportion as the tumour grows. At last it 
becomes horny as it elongates, and forms a kind of sheath which covers externally 
the process of the frontal bone. There are numerous branches of blood-vessels, 
which serve to nourish the bony part, and arc placed between this sheath and the 
frontal bone. 
Tims, the horns arc merely solid, hard, elastic, and insensible sheaths, which pro- 
tect the osseous prolongation of the frontal bone. Tliese sheaths, generally of a 
conical figure, are broadest at the base, or extremity from which tiiey grow. The 
'curvatures assumed by the horns arc different in the several species ; they also pre- 
sent different channels or transverse furrows, depending on the age of, the animal;^ 
^nd these denote, in a very certain manner according to the species, the number oi 
years it has lived. The horns grow in precisely the same manner as the nails of 
'iiumals and the beaks of bird:; that ta to say, from the bone which serves as a base 
^here exudes a gelatinous matter, which takes the form of the horn, and hardens on 
coming in contact with tlic air. M. Vauquelin has found this gluten, or animal 
^mcu 3 , to be of precisely the same chemical nature as that found in hair. 
The texture of the horns appears to bo much tlic same in the Ram, Goat, Antc- 
and Bull. They cotisist of fibres of a substance very analogous to Iiair, and 
^Pl>«ar to be agglutinated in a very solid manner. These fibres in the two genera 
first mentioned arc short, and covered by superincumbent layers like the tiles of a 
bouse. In the last two they are longer, more compact, and form elongated cones, 
^he one being incased \Yithin the other. 
U appears that the horns of the Rhinoceros differ matcrlany from those of the 
^uminantia. They have no osseous part, and are not placed upon the frontal bone, 
but upon the ridge of the nose. They arc formed, however, of tho same substance, 
we observe fibres analogous to hairs more distinctly in this animal than perhaps 
any other. The base of the horn presents externally an infinite number of rigid 
bairs, which seem to separate from the mU'S. and render that part rough, like a 
brush, to the touch. When savNcd transversely, ami examined with a magnifying 
glass, we perceive a multitude of pores, seeming to indicate the intervals resulting 
from the union of the agglutinated hairs. When divided longitudinally, there are 
Numerous parallel and longitudinal furrows, winch demonstrate a similar structure. 
This kind of horn is attached solely to tlie skin. The horns of the Two-horned 
Rhinoceros ( /?/u’noccros always appear in some degree moveable. When 
fixed, as m the Indian Rhinoceros (/?. hidicus), there is a thick mucus interposed 
between its base and tho bone over which it is situate. 
The whalc-bonc, which lines the interior of the upper jaw in the Whales, also 
consists of hair united into laniiiiai. 
The colour of horns depends, like that of the hairs, on the colour of their mucous 
tissue. Heat softens bone, and even fuses it ; hence this agent is largely employed 
in manufacturing them into different articles. 
It appears from these observations, that true horns differ essentially from the bony 
prolongations calleil antlers in the Deer. The latter increase at their extremity, 
and are covered with skin during their growth. They fall off when their growth is 
completed, and are replaced by others, 'file true horns are developed at the base, 
are covered with skin, and remain permanently. 
The Nails of the Mammalia form, with the preceding, useful arms of attack, or 
necessary shields against external injury. These horny prolongations arc generally 
eijuai in number to that of the fingers and toes, whose extremities they serve to arm 
and protect. Their form depends upon that of the last phalanx of each finger or toe, 
and they hear the same relation to those phalanges, as the hollow horns to the pro- 
cesses of the frontal bone which they cover. 
The nails seem to be incased in a fold of the skin, the portion covered by the 
latter being called the root of the nail. They grow by this part precisely in the 
same manner as hairs, but the opposite extremity wears away by friction, from the 
various uses to which animals apply their nails. Accordingly, they are observed to 
grow exceedingly long in animals that are confined, and have few opportunities of 
motion. No part of a nail is sensible, except that wbich adheres to the skin, and 
the free extremity may be cut or broken without occasioning the slightest pain. 
The colour of the nails depends upon that of the mucous tissue. 
The human nails appear in the third month of conception ; and their development 
takes place nearly in the same manner as in the common horns. They appear at first 
like a kind of cartilage, which gradually acquires a proper consistency. Almost all 
animaLs have the nails formed, in some degree, at the lime of their birth. Tlie 
nails of Man, as well as the greater part of the Unguiculated Mammalia, appear to 
be formed of extremely thin layers, placed one upon another. The external lamina; 
are larger than those of the inferior surface ; on which account wc do not readily 
perceive tliis kind of imbrication which actually takes place. When diseased, how- 
ever, or upon making a transverse section of the nail, after it ha? become completely 
dried, this structure becomes evident. Often wc observe stria*, or very fine longi- 
tudinal and parallel lines, apparently resulting from the manner in which this part is 
moulded upon the lamina; beneath it. 
Nails are generally wanting in animals which do not employ their extremities 
cither in walking or grasping, a.s we may remark in the Cetacea. When analyzed 
chemically, the nails aftbrd nearly the same results as hair, to which they bear con- 
siderable analogy, both in structure and their mode of growth. 
Hoofs surround tho phalanx entirely, in which respect they differ completely from 
nails. They are neither pointed nOr cutting at the extremity, and both surfaces 
meet to form a round and blunt edge. Their interior is rendered reinarkabh; by 
deep and regular furrows, which receive projecting lamina; net observable in nails. 
In thu Elephant and Rhinoceros these furrows are very strongly marked. Tliey 
are also conspicuous in the Horse, but do not appear very prominently in the Ru- 
minanlia. A layer of mucous matter may alvrays be observed between the nails and 
the soft parts of the phalanx. In hoofs there is found a soft substance abounding iu 
nerves, which serve to maintain a certain degree of sensibility in these parts. 
Scales may be regarded as very flat horns, in the same way as hairs admit of being 
considered very slender horns. They bear a great resemblance to hairs, feathers, 
horns, and nails, both in their mode of growth and use, as well as in respect to their 
chemical analysis. Only a very few species of Mammalia possess scales on some 
parts of their body, and in Birds they are found on tho feet alone. Reptiles and 
Fishes are, on the contr,ary, almost wholly covered by them. 
The term scales is applied to a variety of substances of very different nature.?. 
In general, they consist of laminEc or small plates of a substance which may either 
be horny or bony. The scales of the animals belonging to the Genus Manis consist 
of a kind of flat nails of a horny substance, but of considerable thickness ; their an- 
terior third, which is bevelled and sharp edged, is free, while they adhere to the skin 
by the other portion. The external surface is channelled longitudinally, particularly 
in the Long-tailed Manis (Manis tetradacttjlu) , in which animal they usually termi- 
nate in three points. They arc furrowed transversely on the side next the skin, and 
appear to be formed of imbricated lamina;. In the Armadilloes, the scales consist of 
small compartments of a calcareous substance, covered with a thick, smooth, and ap- 
pai’cntiy varnished epidermis. The scales covering the tail of the Beaver consist 
of thin laniinm of a horny substance, similar to those on the feet of Birds. The 
tails of Rats, Opossums, and most animaU with prehensile tails, arc covered with 
scales of the same nature. 
GENERAL REVIFAV OF THE MAMMALIA CONTINUED. 
7Vieir Orgaiis of Foirc. 
Man alone of all Mammalia possesses the exclusive privileg'e of uttering articulate 
sounds, to which the great flexibility of his tongue and lips, os well as the general 
form of his moutli, alike contribute. Tho power of commuuicating his ideas by arti- 
ficial words, forms a means of communication of the greatc.st value ; and there ai e 
no signs capable of being employed with tho same convenience for this purpose, or 
which could he perceptible at so great a distance, or in so many directions. This 
faculty of speech, joined to the perfection of tho hand in Man. contr.lmles largely to 
his power. 
The other Mammalia can express their wishes by cries alone; yet these natural 
si-vns are themselves subject to many modifleations. Although incapable of commu- 
.lioating any complicat ’d idea, they at least serve to express tho passions by which 
