THE MAMMALIA— MAN AND BEASTS. 
57 
may differ greatly, but always within certain well-defined limits. Wo may perhaps 
consider the Calmuck variety, with very long, thick, and white hair, as the greatest 
deviation from the original type. 
With the Domestic Hog, tho extreme points of variation must be placed in 
its soft and pendant ears, the smallness of its tusks, and tho union of its hoofs. 
This animal appears to depart most viidely from its original form, when domesticated 
in tho warmest countries; and then the variations in siae and shape are innumer- 
able, and it* colour usually changes to white. That variety of tho Hog with un- 
divided Hoofs, observed long ago by Aristotle, is sometimes found in England ; and 
in Normandy there is said to be a race of Hogs with the fore logs much shorter than 
tho hinder. 
It is, however, in the Dogs that varieties are most striking and important. Man 
has transported these animals into every part of the globe, and the extent of his power 
is seen in the extraordinary (Ufferenccs of their forms. As their unions may be re- 
gulated entirely by the will of (heir master, and as tho connate varieties of 
individuals are readily transmitted to their oflspring, we find among them singular 
deviations from tho original type. Not only is their colour infinitely various, but 
their hair becomes more or less abundant, and soraotimes it is wanting altogether. 
Tho height of some Doga is five times as great as that of others, and their bulk may, 
therefore, be more than one hundred fold. These are not tho only differences. They 
seem to bo acutely suaecptible to all those circumstances which uffcct the growth of 
the different parts of the body. The forms of their nose, cars, and tail; the relative 
height of their limbs; the progressive development of their brain; and the form of 
their skulls, aro alike jiffected by these sources of variation. Sometimes tho head is 
slim, the muKitlo slender, and the forehead flat. Often tho face is fore-shortened, 
and the forehead projects. Indued, the difiercnces between the French ISIatin Dog 
aud the Water-Spaniel, between the Greyhound and tho Bull Dog, are more strongly 
marked than those among many wild anitnals of the same genus, but of different 
species. It is unquestionably in the varieties of the Dog that wo see tho highest 
degree of doviation yet ascertained to prevail among the individuals of any species 
throughout the entire Animal Kingdom. 
Of all tho characters which the domesticated annuals possess, it may be observed 
that the colour of the liair and skin is the most liable to variation. Being placed 
externally, this part of tho body is exposed more than any other to the inflluenco of 
outward causes of change. The hair of the different Dogs exhibits this natural ver- 
satility in a remarkable degree with respect to colour, quality, lengtli, and arrange- 
ment. In cold climates tho Dogs have usually two kinds of hair; the one, being 
short, fine, and woolly, inrimcdiately covers tho skin, while, in the other, tho hairs are 
long and silky. It is the latter kind of hair wliich imparts the coloured appearance 
to the animal. In tropical climates, the fine and warm woolly hair becomes obli- 
terated, and at length wholly disappears. The same thing happens in our houses, 
when Dogs are protected from tho changes of weather and the severity of winter. 
Tho skin of the Barbary Dog is naked and oily; the Bull Dog, the Mastiff, the 
Greyhound, and the Carlin, have the hair short and smooth. It becomes longer in 
the Shepherd Dog, tho Wild Dog of New Holland, the French Mfitin, and the 
Iceland Dog; it ia very long in the Woif Dog, tho Spaniels, and especially in the 
French Biclioii, where it sometimes reaches nearly to tho ground. Again, if the hair 
be viewed in respect to its quality, wc find at least as many shades of difference. The 
Shepherd Dog, Wolf Dog, and the Griffon, havo coarse hair, while in the French 
Bichon, some Waier-Spanitsls, and the Great Dog of the Pyrennees, it. is both silky 
and soft. In some it is straight and sraootli, in other* woolly and curly. Many 
races havo the body clothed entirely with long hair, while on the head and limbs it 
is perfectly thin and smooth. Others, on the contrary, have the head and neck fur- 
nished with a mane, and tho remainder of the body is covered with short hair. The 
Wolf Dog is an instanco of the form<n- kind, and the Lion Dog of tho latter. In 
these respects, wc find in the hair of Dog* all those variations of quality and quantify 
which cau be found in the several genera and species of the Mammalia. Their co- 
lours may Im white, a deeper or paJer brown, faw’n, or black. Some Dogs are seen 
entirely of one of these colours, but most frequently the tints are distributed irregu- 
larly in spots, which may be either large or small. Sometime*! these spots have a 
tendency to become symmetrical; at other limes the longer hairs arc of a different 
colour from the short ones, and then the joint effect of the two colours produces dif- 
ferent shades, according as tho white, black, faw'ii, or brown, predominates. Thus, 
We may see Dog* with hair ap^iarently resembling that of the Wolf, and upon a closer 
examination this is found to proceed from the mixture of white, fawn, and black 
bairs ; or more rai’oly tho general effect may produce a gray slate colour. These co- 
lours are not connected with any particular variety, nor does it necessarily follow that 
Dogs of different colour.s must be further distinguished by tho forms of their heads, 
the quality of their hair, or the proportions of their bodies. It usually happens, in 
all tliese cases, that when care is taken always to unite individual* of the same colour, 
form, ajid size, that the race perjK'tuatcs itself. It is from the constant union of indi- 
viduals having the same, or nearly the aamo, colour that tJie Danish Dog, Grey- 
bound, Bull Dog, and Mastiff, are fawn, the yhepherd Dogs are black, the Wolf Dogg 
v^bite, and tho Gallic Hound, the Braques, Bassets, and Spaniels, have block spots 
’^Pon a white ground; but Avhen this precaution is not observed, tho colours of tho 
above-mentioned Dogs will be modified in proportion to their degree of admixture 
with other races. However, thu connate modifications of colour, as well as tha 
more important one* of sliapc aj;d. size, nsually end in becoming hereditary, when they 
*ire not counteracted by some neutralizing cause. 
Thus wc iind, upon the whole, that the more important variations of the Mammalia 
may be ranged under the following heads 
L The skull and face may bo shorter or longer, broader or higher; the forehead 
bo elevated as in the Wild Boar, or depressed as In tho domestic Hog. Thus, 
the head of the Ncaiiolitaii Horse differs remarkably from that of Hungary and 
raiisylvania in tlie shortneas aud breadth of its lower jaw-bone. Camper also rc- 
maiked, that the lachrymal depressions (jutetz laclmjmaU&)^ wliieh can be clearly 
o seived in tho Wild Bull, had disappeared by degeneration in the domestic 0:^. 
2. 7 he general figure and proportion of the limbs may be altered to a most ra- 
Ij 
markable extent. Wc see striking instances of this variation on comparing the 
Syrian and Arabian Horses with those of the North of Germany and the Shetland 
Isles. 
3. In stature there may be a singular disparity; thus, the Hogs transported to the 
Island of Cuba acquire a size nearly double that of the common European Pig ; and 
a very considerable growth takes place among the Wild Cattle of Paraguay. 
4. The texture and quality of the Hair may vary from tho soft wool of the Thibet 
Sheep to tho dense and .almost rigid hair of tho Ethiopian variety. In Normandy, 
tho bristle* of tho common Pig lose all their stiffness. But the most singtdar m- 
stanccs of "VTiriation in the hair are effected by the climate of Anatolia, where this 
cause equally affects different species of Mammalia, and transforms tho short fur of 
our Cats and Babbits, as well as the wool of our Sheep, into the long and silky fleece 
of the Angora varieties. 
Lastly, tho colour of the Hair may vary from black to white through all the shades 
of brown or red. The fleeces of Angora often assume a silvery whiteness. Indeed, 
we have only to look around us to see innumerable inetanccs of diversity in the colours 
of our domestic tinimals. 
GENERAL REVIEW OF THE MAMMALIA CONTINUED. 
JPermanence of Species — Difficulties in distinguishing between Species and 
Varieties, 
As the variations which have arisen among tho Domestic animals, and especially in 
the Dog, appear very considerable, it has been thought probable by many Naturalists 
that our different races of Dogs have descended from se^•era] distinct species. In 
this way the difficulties of explaining the causes of their variations are wholly avoided, 
rather than resolved. It remains to be shown, under this view of the subject, from 
how many species the domestic Dogs have descended. No Naturalist could propose 
to establish a species for every distinct race, which arc upwards of fifty in number. 
Still less, as all these races are capable of forming crosses with each other, could they 
institute a species for every combination in pairs; nor could they extend it to those se- 
condary and tertiary crosses which might be formed among their posterity, both with 
each other and with the original races, thus rendering the number of species abso- 
lutely infinite. It has been rather attempted to limit the sources of the several races 
of Dogs to a small number, raarkod by important differences. Yet it becomes equally 
impossible to point out the particular stocks from w'hich these races have descended 
or the variations which must be regarded as important, without falling under objec- 
tion* of another kind. 
There are several considerations v^hich clearly establish the important fact that 
Species have ii real existence in Nature; — that certain forms have been assigned to 
each animal from the origin of things; and that although the animals are liable 
to diverge from their primitive forms, they always possess a preservative tendency, a 
nistis formativi/jf and are ever ready to revert to the original type when the external 
causes of change arc removed. The entire Animal Kingdom is divided into a num- 
ber of distinct species, each of which perpetuates its own form, without ever trans- 
gressing certain limits, or acquiring the characters of another species. 
In all the varieties observed to arise among tho Mammalia, tlie form of the bones 
preserves a remarkable stability, which would not always be expected from tho ap- 
pearance of the external parts. The. Baron Cuvier compared the skulls of Foxes 
from the North of Europe and from Egypt with those of Franco and with each otlicr 
yet he found no other diflferenecs than such as might distinguish one individual from 
another. The antlers of the Hein- Deer and Stags often vary in size, and the 
same may happen with the tusks of tho Elephant; but two individuals of any one of 
those species, however dissimilar they m.ay bo in size, do not exhibit the slightest 
difference in the number of their teeth, or tho articulations of their smallest bones. 
This is also observed with the domestic Cattle, which may bo destitute of horns 
or have them of variable length, and yet they possess an exact correspondence in all 
the otiier parts of the skeleton. 
Thus tho forms of the bones in general vary but little; while their modes of con- 
nexion, their articulations, and the form of the great molar teeth, remain constantly 
the same in each species. The divided Hoof of the Hog sometimes becomes consoli- 
dated, and this may be regarded as the extreme limit of variation amonf^ the bones of 
our domestic herbivorous animals. 
The variations of the bones in the different kinds of Dog have undergone a special 
examination by M. Frederic Cuvier, performed at tiie request of his brother upon tho 
specimens at tho Museum d' Histoire NaturcUe. To enter fully into tlie details of 
this investigation would at present be out of place- It will suffice here to mention, 
that a general correspondence in all the parts of their skeletons was found to exist, 
and at the same time some important variations, especially in the degree of elevation 
of tho frontal sinuses. The teeih were always of the same number and general form ; 
sometimes an additional false molar, or a tubercle, was observed on one side or on tho 
other. It is well known that all Dogs have five toes on tlie fore-foet, a.td only four 
on the hinder, while there is a slight trace of a rudiramtal fifth foe in the hinder 
metatOTKal hone, which, however, shows no appearance on tho outside. Tliese toe? 
being of unequal length, usually preserve the same relations in all the races ; but 
sometimes a fifth toe exhibits itself on the internal surface of the hinder-feet. It is, 
however, generally very short and imperfect, and this last is the maximum of varia- 
tion found in the skeletons of all tho races of Dogs. 
It thus appears abundantly evident, that animals now possess certain characters 
which remain permanent, and resist all modifications, whether arising from climate or 
domestication, or from a natural tendency to run into connate varieties. 
Time, however, it has been said, may effect a perceptible modification in the entire 
characters of species. Fossil remains, and otlior Geological monuments, appear to 
show that millions of years have elapsed since the first species of animals inhabited 
the earth, and it is asked, may they not have undergone many modifications during 
the interval ? 
