CHAMBERS'S INFORMATION FOR THE PEOPLE. 



varied materials of which it is composed, all the 

 complicated actions, reactions, and mutations to 

 which they are subject, are humble phenomena 

 compared with the production of the lowliest or- 

 ganism. This life is everywhere : the waters teem 

 with it, the dry land from pole to pole is clad with 

 it ; nay, there is life within life, and perhaps there 

 exists not a single plant or animal but becomes 

 in turn an abode for others of more diminutive 

 dimensions. Speculations as to the origin and 

 generic classification of vegetable and animal 

 life belong not to our subject. Geography views 

 them simply as they exist, and endeavours to 

 determine the laws which regulate their distri- 

 bution. 



Vegetables are regulated in their terrestrial dis- 

 tribution by conditions of soil, heat, moisture, light, 

 height of situation, and various other causes ; in 

 the waters, by depth, heat, light, nature of bottom, 

 and the presence of mineral and saline ingredients. 

 Were it not for these causes, there is no reason 

 why the tribes and genera of one region should 

 not be identical with those of another why the 

 palms of India should not flourish alongside the 

 oaks of England, the oaks of England with the 

 pines of Norway, or these again with the dwarf 

 birches of the arctic regions. As it is, the tropics 

 have genera unknown to the temperate zone, 

 and every advance poleward brings us in contact 

 with new and peculiar species. Temperature in 

 this case seems to be the grand regulating con- 

 dition ; and as this is effected by elevation, as well 

 as by increase of latitude, we find the mountain- 

 ranges near the equator presenting all the features 

 of a tropical, temperate, and even arctic vegeta- 

 tion. Thus palms and plantains may luxuriate at 

 their bases ; then appear oranges and limes ; next 

 succeed fields of maize and wheat ; and still higher, 

 commences the series of plants peculiar to tem- 

 perate regions. In temperate latitudes, though the 

 variety of vegetation be less, similar phenomena 

 present themselves. Besides these great climatic 

 effects, there are others depending on soil, mois- 

 ture, light, &c., which, though limited, are not less 

 imperative. Thus, the southern slope of a hill is 

 generally clothed with species distinct from those 

 on the north ; a limestone district presents a carpet 

 of vegetation widely different from that of the 

 clayey moorland : some tribes flourish in the moist 

 valley, which would die on the open plain; some 

 tribes thrive in the marsh, others on the dry upland ; 

 some luxuriate under the influence of the sea-spray, 

 which would be instant destruction to others. But 

 whilst most species are subject to these laws, there 

 exists in the constitution of many a certain degree 

 of elasticity which admits of their adaptation to a 

 wider range a beneficent arrangement, which 

 permits man to extend through cultivation those 

 grains and fruits upon which his subsistence so 

 essentially depends. (For further and more minute 

 information respecting the laws which regulate the 

 dispersion and distribution of plants, see VEGE- 

 TABLE PHYSIOLOGY.) 



The animals which people the globe are sub- 



64 



jected to somewhat similar laws of distribution. 

 Some are strictly tropical, others confined to the 

 temperate zone ; while not a few are destined to 

 find their subsistence wholly within the polar 

 circles. Besides this general distribution, we find 

 a more particular restriction to certain continents 

 and tracts where peculiarities of soil, climate, and 

 food seem to be the governing conditions. Thus, 

 the elephant roams only in India, Burmah, and 

 Africa ; the ostrich in Africa ; the rhea in the 

 pampas of South America ; the kangaroo in Aus- 

 tralia ; the reindeer within the arctic circle ; 

 the polar bear amid the snows of Greenland and 

 Labrador ; and so on, as will be more minutely 

 shewn under ZOOLOGY. Similar laws are im- 

 pressed on the life of the ocean. The ' right ' 

 whale, as it is termed, of the northern hemisphere, 

 is a different animal from that of the southern ; for 

 ' the tropical regions of the ocean are to him as a 

 sea of fire, through which he cannot pass, and into 

 which he never enters;' while the sperm whale 

 delights in warm water. The herring finds its 

 chosen habitat in the Northern Sea ; the oyster 

 clings to a peculiar bottom, at a certain depth ; 

 the cod inhabits the same banks and shoals for 

 ages ; and a few fathoms of greater or less depth 

 would be more fatal to many species of shell-fish 

 than the dredge of the fisherman. As on plants, 

 so on animals, altitude exerts a very decided influ- 

 ence ; and we do not exaggerate when we affirm 

 that a lofty mountain-range presents a more im- 

 passable barrier to vital distribution than the 

 widest expanse of ocean. Though presenting a 

 close analogy in the manner of their distribution, 

 plants and animals differ in this respect, that 

 many tribes of the latter birds, fishes, and mam- 

 malia make periodical migrations of vast extent ; 

 food and proper breeding-places being the objects 

 of their search. These migrations must not be 

 confounded with that adaptability of constitution 

 which fits the horse, the dog, the ox, the sheep, 

 the pig, and other domestic animals, to be the 

 companions and supports of man in his onward 

 possession of the globe. The one is but a change 

 of place in search of food, under a congenial tem- 

 perature ; the other amounts to a constitutional 

 change, irrespective of climatic influence. 



Man, of all animals, has the widest geographical 

 distribution. This he enjoys not only from the 

 greater adaptability of his constitution, but from 

 that superior intelligence which enables him to 

 counteract the effects of climate by clothing, 

 houses, fire, and the storing of provisions. It may 

 be justly affirmed, therefore, that there is no region 

 where man may not exist and carry on the pur- 

 poses of life in a higher or lower degree of civil- 

 isation. Though generally regarded as a single 

 species of a single genus, naturalists have divided 

 mankind into several varieties, according to their 

 more prominent physical features; and ethnolo- 

 gists, extending the subject according to minor 

 features, language, and so forth, have subdivided 

 these varieties into branches, tribes, and families- 

 See ETHNOLOGY. 



