« ForrigeFortsett »
Greece, and is particularly described by Zenophon.* For this purpose speed could be of little service, but acuteness of smell to investigate and follow the course of the animal pursued would become essential; hence would result an improved sagacity and more exquisite sensibility in the olfactory organs.
The Wolf has, with great probability, been supposed to be the Dog in a state of nature; but should this supposition not be correct, there is every reason to believe that the original Dog must have closely resembled him in form and habits. The Australasian Dog is so like the Wolf, that naturalists have not decided whether he be a Wolf or a Dog: he ought, perhaps, to be considered as a Wolf in a semi-domesticated state. The author of this paper has been informed, by his highly-respected friend, Mr. Mungo Park, whose evidence on every subject is entitled to the most implicit reliance, that the Dogs of the interior of Africa are of tawny. colour, and formed much like the Wolf. lle did not recollect having seen any Dogs in a perfectly wild state ; but those halftamed animals which he met with, were by no means faithful or obedient servants: they seldom bark, and often bite slily without provocation; and although they seem to know their names, they refuse to attend a call unless allured by the offer of food. These Dogs are all of the same form and size, at least as equally so as wild animals in general, and he never saw in any of them a variation of colour: they hunt by scent, and course by sight, according to circumstances, after the manner of wolves. It is a law of nature, that those parts of animal bodies which are most called into action increase in size and power: in like manner, parts little exercised are enfeebled and diminished. To the influence of this law, the author of this Essay has been led to refer all the varieties of form induced on domesticated animals: some seeming exceptions may occur, but more extensive physiological experiments and anatomical knowledge will probably explain them. This law extends equally to the organs of sense,---hence the origin of induced instincts : to hunt their prey by scent when out of sight, or to course it when in view, is the natural habit of the canine tribe: on this natural disposition all the artificial instincts observable in many domesticated varieties seem to have been induced. One law, then, appears to operate both upon the instinct and form; and when called into effect through several generations, its influence becomes hereditary. By breeding from the fleetest and lightest formed dogs, and using them solely for coursing, the race of Greyhounds has probably sprung: the slow, rough-coated Hunt. ing-dogs have, it is inferred, becn produced, by similar cultiration through continued descents, and thus have attained their peculiar characteristic qualities.The young Pointer stands the first covey; but to point is obviously an induced instinct,—with such a propensity a wild animal must necessarily starve. Birds, also, are not the natural prey of dogs : indeed, it rarely happens that any Sporting-dog will eat the game he hunts. The Pointer is a va. riety of the Hound; but by long training, through successive generations, his peculiar mode of hunting and standing his game has been, as it were, engrafted on him ; so that the re ult appears like a purely natural instinct. Other breeds have induced forms and instincts still farther removed from nature:-the young
* Vide Cynegeticoo.
Bulldog flies at the first bull; the Truffle-dog instinctively discovers that particular mushroom; the Sheep-dog takes charge of the flock; and the Mastiff, of the yard and his master. In these last-mentioned varieties, Nature's propensities seem to be almost entirely superseded by artificial instincts.
In a short Essay, designed merely to excite investigation, the experiments and observations which have led to the infe. rences contained in it, cannot be detailed; but the simplicity and comprehensiveness of the law which the author presumes to be the cause of varieties in animals, is perhaps no weak argument of its truth,--for nature is ever simple in her general operations. The opinion that all the adaptations of structure exhibited in the animal world are solely the effects of internal organization, has often been adduced to invalidate the Mosaic history of the creation. Urged to the greatest possible extent, it is indeed but a feeble argument; but restricted to the limits which science and reason prescribe, it seems strongly to confirm the sacred record. If pairs of every species of living beings, first placed on a particular spot, were destined to spread and inhabit every part of the globe, it seems absolutely necessary that each species should be endowed with certain powers of accommodation, to sustain the changes of climate and circumstances to which their dispersion would expose them : the degree of these powers, in different classes, is certainly various; but, could it be ascertained and acted upon philosophically, many animals, now deemed untameable, might be subdued to the pleasure and service of mankind. The Laplander has yoked his Deer, because the Horse was not the inhabitant of his inhospitable climate: the antlered tenant of our forests has escaped subjection, because animals better adapted to our purposes were supplied : the Zebra is wild, because the African is indolent; and the Rhi. noceros is still unsubjected, because the Camel, the Horse, and the Elephant, have made his strength unnecessary to the Hindoo.
Are animals of the most complex anatomical structure endowed with the greatest ability to accommodate themselves to imposed circumstances ?-Man exists in every climate, and on every kind of food : he is capable of sustaining extreme cold, and a degree of heat much greater than that of boiling water. (Vide the Experiments of Dr. G. Fordyce, Sir Charles Blagden, and Philosophical Transactions.)-Mr. J. Hunter kept a Sheep on animal food, and a Ilawk on grain; and Cows in Sweden are fed, during the winter months, on salted fish alone. The Mammalia and Aves, in general, can sustain great changes both of temperature and food; whereas most insects and worms can exist only in very limited districts, some only on particular plants, others are even confined to particular parts of plants, and seem to be incapable of supporting life under any change. On the contrary, Dr. Robert Ilook, whose genius was kindred to that of Bacon (who pointed the way to the most important modern discoveries), seems to infer, that very minute animals have the greatest power of adapta. tion. He observed on his window a very small insect, much resembling a mite; * and he conjectured that he had discovered the vagabond parent of those Mites found in cheese, meal, corn, musty barrels, leather, &c.” He remarks, « that those little creatures, wandering about, might perhaps be attracted by the putrifying steams to spend the remainder of their lives,-a day perhaps,---in such places, and leave their offspring behind them; which hy the change of soil and country may become altered from their progenitors, as Moors, translated into Northern climates, after a time change their skin and shape. And this seems more probable in these insects, because the soil they inhabit seems to be almost half their parent,---for it not only hatches their little eggs, but seems to augment and nourish them before they are hatched; for it is obvious that the eggs of many insects, particularly of Mites, are increased in bulk after they are laid out of the bodies of the insects, and plumped up to many times their former bigness. But though this is probable, I am not certified in my observations.”-It may also be objected, that animals are perfect in anatomical structure, as those domesticated species which have assumed the most remarkable accommodations have undergone no change, either in figure or propensities, by the united influence of confinement and change of climate. Tigers, and other wild beasts bred in the dens and menageries of Europe, have retained the ferocious dispositions of their original kind;
* Vide Micrographia, p. 205.
nor have they acquired any provision to support the change of temperature which must materially affect them. But such instances are not conclusive : the first steps of alteration may
be too slow to be observable in a few generations; and, probably, the too sudden transition of climate may so affect the constitution as to render it incapable of the necessary efforts: the treatment, also, which these animals usually experience,--the frequent provocations offered them by persons who visit them from vulgar curiosity, and their constant confinement, which alone renders fierce our domestic Dogs, are obvious impediments to the improvement of their docility. What effects might result from more judicious treatment is uncertain; but it seems probable, that con. siderable changes would ensue. Animals nearly allied in figure and habitude (for example, the Cheta, Felis Jubata of Linnæus) have submitted to the authority of man, and become his assistants in the chase. Without doubt, the attainment of new physical powers, and indeed, instincts, even in the most docile tribes, must have advanced by slow progression. Dogs are described by Homer as following the Grecian army and preying on the dead, a state much resembling the African Dog, mentioned in the first part of this Essay; and the Siberian Dogs, to this day, run wild during the summer months, and only submit to a reluctant and untractable servitude, when winter compels them to seek subsistence in the huts of their masters. The Australasian Dog approaches still nearer to the unsubjected state than the Siberian : like the Dogs of Africa, he has not yet assumed the early alteration of colour, which seems to precede all other changes, probably because the epidermis * is most exposed to external in. fluences.
In wild animals, Pied varieties are very uncommon; their colours distinguish each species with remarkable regularity: the offspring of domesticated animals, on the contrary, deviate much in their marks and hues from their progenitors. Those cows kept in parks called Sheet cattle, the body only being white, as if a sheet were wrapped round it, continue their breed unchanged; but Oxen in general, and almost all other domestic animals, have rarely any modification of colour that is unvaryingly hereditary. From some chemical observations on the effects of Light, it appears that the colours both of animals and vegetables are greatly influenced by it. Plants become blanched if light be excluded from them; and Rabbits bred in the dark cellars of London, after many generations, are sure to become white. Whether any arti. ficial regulation of light might produce a corresponding change an animal, has not been ascertained by modern naturalists;
* The external skin, hair, and nails.
but the very explicit account of the mode adopted by Jacob to influence the colour of the 'flocks of Laban, is no less curious than worthy of experimental research. Alterations in the mus. cular structure and skeleton of animals succeed the change of colour, and require a longer influence of imposed habits to produce them. All the muscles necessary for swiftness,--the glutæi psæ, &c. are of great bulk in the Greyhound; and their increase of magnitude, with the diminution of those not called into action by the purposes for which this animal is bred, -as the muscles of the neck, jaws, &c. contribute chiefly to constitute that exterior character which distinguishes this variety. The Bull-dog has been trained to bite and hold resolutely whatever he seizes on; the muscles therefore of his neck and jaws are remarkably large and full. The foot of the Newfoundland-dog, by extending his toes in swimming, is become broad aad palmated, and the membrane which connects the toes is stretched so as to act like the webbed foot of water-fowl. Induced instincts accompany these great changes, and are hereditary with them. It must, however, be confessed, that in animals long domesticated some changes have taken place not referable to any known law :-Sheep-dogs are in this country generally born without tails: some breeds of Pointers are born with tails terminating at the precise length at which sportsmen generally cut off this part. There is also a well. known race called Double-nosed Pointers, which have the nostrils longitudinally divided by a fissure that extends to the termination of the frontal bone, and descends into the mouth so as to divide the palate as far as the first transverse ridge. The alteration of structure in each of these breeds is hereditary, and descends to cross breeds in an intermediate degree.
From the loose and desultory observations contained in this Essay, the Author does not flatter himself that he has legitimately proved any one fact or position_his object is to excite investigation, and he feels confident, that if the subject be philosophically pursued, without deviating into the extravagancies of system, the result must be replete with instruction and utility.
ART. XVIII.-A Farewell to Tobacco.---By C. LAMB.
May the Babylonish curse
In this word-perplexity,