REALMS OF PLANTS AND ANIMALS. 567 



the globe. There might, too, be added every variety of character and 

 every degree, of intellectuality. Among these differences, the variations 

 of language are by no means the least important. It is estimated that 

 more than three thousand dialects are spoken. 



Among these races certain common traditions prevail, historical rem- 

 iniscences handed down from one generation to another, Traditions of 

 which convey the deeds of former great men who have either B ation s> 

 distinguished themselves by their achievements in war or by their in- 

 ventions in the peaceful arts ; traditions which have also communicated 

 the religion or the superstition of the ancient times, and which, among 

 people inhabiting countries remote from one another, present such an as- 

 pect of sameness, that we must either refer them to one common and more 

 ancient source, or regard them as arising from analogous peculiarities in 

 the mental structure of the whole race. 



There can not be a doubt that in the lapse of many ages the influ- 

 ence of external physical agents must have made a marked i nfluenceofex 

 impression upon the original characters of men. Few ques- temai agents 

 tions have been more critically discussed than the extent to 

 which this change of aspect by physical agents can go, many naturalists 

 believing that the sole cause of national difference is the influence of cli- 

 mate or temperature an influence which is sufficient to account for all 

 other organic peculiarities we have just specified ; for if we admit that 

 the same original germ may develop itself into countless forms, accord- 

 ing as it has been exposed to different physical agents, much more is it 

 probable that the various races composing the human family, exposed as 

 they have been to different physical circumstances, may by degrees have 

 assumed the discordant features they present, although they have de- 

 scended from one original stock. 



Here we shall have to consider the weight which should be attached 

 to a very remarkable observation which has of late been Geographical 

 made as respects the distribution of man. -With regard to 'JSJ^'* 

 plants, it has long been known that they are grouped round mais,andman. 

 certain centres, which may be regarded as their foci of origin, and one of 

 such groups compared with another presents striking contrasts ; the veg- 

 etation of Central Africa is wholly distinct from that of Europe, the veg- 

 etation of Europe distinct from that of North America, and this, again, 

 from New Holland. There are no lauringe in Central Africa, no heaths 

 in the New World. The forests of New Holland gain their most strik- 

 ing features from their leafless acacias and eucalypti. So, in like man- 

 ner, there are foci of origin and circles of distribution as regards animal 

 life. The fauna of Asia is wholly dissimilar from that of Europe, the 

 fauna of Europe is dissimilar from that of North America, and this, again, 

 from that of Africa and New Holland. Without specifying details, we 



