PHYSIOGNOMY OF PLANTS. 217 



land, in regions characterised on every side by the most 

 exuberant vegetation, is a geological phenomenon which has 

 hitherto received but little attention ; it undoubtedly arises 

 from former revolutions of nature, such as inundations, or from 

 volcanic convulsions of the earth's surface. When once a 

 region loses its vegetable covering, if the sand is loose and 

 devoid of springs, and if vertically ascending currents of 

 heated air prevent the precipitation of vapour (9), thousands 

 of years may elapse before organic life can penetrate from 

 the green shores to the interior of the dreary waste. 



Those who are capable of surveying nature with a compre- 

 hensive glance, and abstract their attention from local pheno- 

 mena, cannot fail to observe that organic development and 

 abundance of vitality gradually increase from the poles to- 

 wards the equator, in proportion to the increase of animating 

 heat. But in this distribution every different climate has 

 allotted to it some beauty peculiar to itself : to the Tropics 

 belong variety and magnitude in vegetable forms; to the 

 North the aspect of its meadows and the periodical renova- 

 tion of nature at the first genial breath of spring. Every 

 zone, besides its own peculiar advantages, has its own distinc- 

 tive character. The primeval force of organization, notwith- 

 standing a certain independence in the abnormal development 

 of individual parts, binds all animal and vegetable structures 

 to fixed ever- recurring types. For as in some individual 

 organic beings we recognise a definite physiognomy, and as 

 descriptive botany and zoology are, strictly speaking, analyses 

 of animal and vegetable forms, so also there is a certain natural 

 physiognomy peculiar to every region of the earth. 



That which the painter designates by the expressions 

 " Swiss scenery" or " Italian sky" is based on a vague feel- 

 ing of the local natural character. The azure of the sky, the 

 effects of light and shade, the haze floating on the distant 

 horizon, the forms of animals, the succulence of plants, the 

 bright glossy surface of the leaves, the outlines of mountains > 



