DISntlBUTION OF PLANTS AND ANIMALS.] 



METEOROLOGY. 



1201 



show how much the natural clothing, <tc., of the animal 

 becomes self-adaptable to climatic extremes, and ex- 

 cessive ranges in the temperature of the seasons. 



Considerable analogy subsists, in general, between the 

 external and protecting coat of trees and animals. The 

 txogeiwus kind of plants, such as all the trees of this and 

 other cool countries, are furnished with a thick bark, 

 which affords a most essential protection to the tree 

 during its growth, and the removal of which would cause 

 its destruction. In endogenous* plants, as the palms, 

 bamboo, sugar-cane, etc., which are confined to tropical 

 countries, this cuticle, or bark, if any exist (which has 

 been disputed), is of the most elementary kind ; and, 

 after a certain period, not only does it not increase, but 

 seems to prevent the stem also from increasing in 

 width ; hence the endogens are almost invariably tall 

 and tapering plants, bearing flowers and fruits only at 

 their upper extremities. It has been considered, indeed, 

 that the "bark" of the endogens is nothing more than 

 the hardened external cells of the stem ; whilst that of 

 the exogens is a true and complete sheath, regularly 

 produced during the growth of the tree, and essentially 

 connected with its vitality. 



With respect to the growth of food specially adapted to 

 certain species of animals, and which we have already 

 noticed in. respect to cattle, horses, sheep, &c. , we may 

 add a few more instances that are well worthy of notice, 

 as indicative of the climate of many regions. The deer 

 tribe are very fond of certain kinds of lichens, and both 

 I .lants and animals begin to be simultaneously de- 

 : 'ed as the climate becomes suitable for each. In the 

 north of Scotland, for example, wild deer are scattered 

 sparsely, and so is their lichen-food ; but as we proceed 

 further north, as in Lapland, Iceland, and Greenland, 

 both the aiiimal and vegetable which are, comparatively 

 speaking, a curiosity in our country become essential to 

 the existence of the inhabitants ; the lichen ialandiciu, or 

 Iceland moss, for example, being an abundant and 

 characteristic production of that country. 



Taking an extreme case of a similar nature, let us 

 transfer our observations to a climate of an entirely 

 opposite character namely, that of the parched deserts 

 of Northern Africa and Arabia. The herbage produced 

 is at once scanty and coarse, and utterly unfit to support 

 horses ; but the camel . feeds well on it, and is also 

 enabled, by its peculiar constitution, even to accumulate 

 a kind of stock of food, in the shape of the fat which forms 

 its humps, and which are gradually assimilated into the 

 system whenever its ordinary food cannot be obtained. 

 Its stomach is so arranged in deep cells, as to enable it 

 to retain a store of water when necessary, the cells being 

 expanded or contracted by the voluntary or instinctive 

 action of the quadruped. If taken far northward, it is 

 removed from its natural sphere, and will die, in places 

 where the horse tribe are produced in the greatest 

 numbers, and in the best condition ; yet the llama, 

 which is the camel of South America, is impatient of 

 heat, and, being a native of the Andes, frequently 

 retreats, in warm weather, to the snow-line gene- 

 rally living in flocks, at a great altitude above the sea- 

 level. In Peru and Chili, the llama is employed as a 

 beast of draught ; as is the camel in Arabia and Africa ; 

 and, like it, affords food and clothing to the natives of 

 those rocky and mountainous countries. Singularly 

 enough, it varies from the camel (whose feet are adapted 

 for walking on sand) in having completely divided toes, 

 which are thus so suitable for climbing the rocks ; and 

 also in the absence of humps, which its more abundant, 

 or perhaps extensively diffused, food renders unnecessary. 

 Its clothing is a woolly hair, remarkable for its warmth, 

 and it effectually protects the animal from the sudden 

 changes of climate that occur in travelling from the plains 

 to the mountains, so universal near the western coasts of 

 South America, t 



It will have been gathered from the preceding remarks, 



The terms "exogenous" nnd "exonens" are applied to such trees 

 a* the oak, rim. npple, &c., which increase in bulk by a growth otu-ardty ; 

 whilst " endogenous" and "endopens" are referred to such as grow 

 iiiKaid/y, as the palm-tree, common wheat, gnu, &c. The former 



VOL. L 



that certain species of animals are only found in 

 definite tracts or zones. Such localities have been 

 termed specific centres ; and it is from these that animals 

 of certain species have been spread, accidentally or 

 otherwise, in countries to which they do not naturally 

 belong in a like manner, indeed, to the transplantation 

 of objects of vegetable growth into climates similar to 

 those in which they grow naturally. In judging of the 

 original place of any species, it must be borne in mind, 

 that influences besides those of climate are constantly 

 active in effecting changes ; and none, perhaps, more so 

 than the progress of civilisation. Man has driven before 

 him many animals from their ancient haunts ; as, in our 

 own country, the wolf, bear, hysena, beaver, &c., have 

 long been extinct. In geology, we are often able to 

 judge of the climate which must have existed ages ago, in 

 many places, by finding fossils of certain animals, 

 comparing them with existing species, and inferring, 

 from the habits of such, what must have been those of 

 their ancient families. An instance of this kind is 

 presented by the fossil elk of Ireland, which has un- 

 doubtedly existed since the creation of mant It is, 

 therefore, highly essential that the exact specific centre 

 of any recent and existing species should be carefully 

 ascertained, as otherwise, in the comparison of them with 

 fossil remains, serious errors may arise. Occasionally we 

 meet with animals whose specific centres are so exactly 

 shown, as to leave no reasonable doubt of their being 

 confined to one region. Of this kind are the Omitho- 

 rhyncidce and Echidnidce, natives exclusively of Australia 

 and Tasmania. These two families resemble each other 

 in some respects : the ornithorhynchus, however, is dis- 

 tinguished by having the jaws precisely like the bill of 

 the duck, with a body resembling that of the ordinary 

 quadruped ; many of the organs, &c., presenting analogies 

 to that of the birds. In the echidna, the snout is 

 produced into a long cylindrical organ, the body being 

 thick and short, and covered with hairs. These two 

 families are certainly paradoxes in natural history, and 

 afford remarkable instances of the restriction of animals 

 within certain specific centres. J 



Perhaps we may be indebted for the discovery of these 

 singular creatures (and entertain the hope of many more 

 in the Australian continent), to the fact, that man has, 

 as yet, done little there in "improving" its immense 

 extent of uncultivated, and, indeed, unexplored territory. 

 Not only does civilisation wage war with the brute 

 creation but even our own species, when found as 

 aborigines in any country, soon undergo a similar fate, 

 as may be witnessed in nearly the whole of the northern 

 portion of the American continent, but especially in that 

 called the United States. In many parts, wholesale 

 extermination, or extradition, has been resorted to, 

 especially in the southern districts ; and the destruction 

 of the aborigines by the Spaniards, in other parts of the 

 continent, are too fresh in the minds of our readers to 

 require recital here. In most instances, the original 

 inhabitants, where undisturbed and completely accli- 

 matised, live happily and healthily in regions which are 

 almost surely the grave of the intruding white man. 

 The coasts of South America, Western Africa, &c., 

 afford illustrations of this fact, and astonishingly declare, 

 even in the case of the almost ever-accommodating con- 

 stitution of our species, that we are subject to the law of 

 specific centres, the removal from which may be pro- 

 ductive of danger, or extinction in some cases only, 

 under any circumstances, to be provided against by 

 an intelligence of which the lower kinds of animals are 

 entirely destitute. 



But although quadrupeds seem unable to exist in 

 other than climates similar to that in which they are 

 native, except under special circumstances as when 

 under the care of man and, further, cannot shift from 

 place to place, in cases of sudden changes of temperature, 

 fur any great distance ; we find amongst the birds a 



increase constantly bulk In width and height; but the latter, after a 

 Certain period, grow in height alone. 



+ Steatite, p. 1196. 



See pp. ill, 4lJ-Vol. IL 



70 



