164 WHAT DOES MAN LIVE UPON? 



brought to a scanty vegetation, if these prepare the soil for 

 better plants by their decay wherefore occurs, in spite of 

 any supply of humus, so great a difference in vegetation ? 

 Why does one and the same plant thrive most luxuriantly on 

 this soil, while on that it is stunted, or does not develop at all? 



"Non omnis fert omnia tellus, 

 Hie segetes, illic veniunt felicius uvse." 



VIRG. GEORG. 



" Not every soil, each grateful gift supplies, 



Here waving corn there, happier, vineyards rise." 



The beautiful Orchidaceous plant, the Ladies'-slipper, 

 grows over all parts of the Swiss Fore- Alps, where the soil 

 is formed of the Alpine limestone ; it accompanies the 

 whole Swabian Muschelkalk, and disappears suddenly when 

 we come to the sand of the Jura and Keuper formations on 

 this side of the Danube. It next makes its appearance on 

 the Muschelkalk of Thuringia, and comes down with that 

 on the Werra as far as the neighbourhood of Gottingen, 

 then leaps over the Bunter-sandstone of the lower Eichs- 

 feld, the granite of the upper Hartz, and again gladdens 

 the eye of the wanderer on the calcareous formations east- 

 ward of the Brocken. It is sought in vain over all the 

 clay and sand formations of the northern German plains, 

 till in the extreme North it again shows itself, at Riigen, 

 where the chalk rocks of Arkona and Stubbenkammer lift 

 their heads. On the western coast of France grow various 

 insignificant-looking shore-plants, species of Salsola and 

 Salicornia, which the inhabitants there use to obtain soda 

 from the ashes. When we travel from thence toward the 

 east, we everywhere miss these little plants, even when 

 searching most carefully, and merely one or other of them 

 makes its appearance in such places where the soil is 

 moistened by some salt spring. At last we arrive at the 

 great Steppes of the south-east of Russia, which in summer 



