THE ORGANISMS OF THE SOIL 



By E. H. L. SCHWARZ, A.R.C.S., F.G.S. 

 Rhodes University College, Grahams town, South Africa 



To Liebig and the early investigators of the soil, the processes 

 of decomposition which obviously take place in it were the 

 results of purely chemical action. But the more the soil was 

 investigated, the more this explanation became untenable. 

 There was discovered in it a teeming race of animals, as well 

 as of plants, of an order different from those which live upon 

 the outer surface ; a race of minute organisms distinguished in 

 essential characters from the larger forms which had been 

 thought to be the only tenants ol the globe. In these dwarfs 

 the living substance of those which had their being in Archaean 

 times is alive to-day. Brought into existence to destroy, 

 to break up the rocks of the primitive earth, to prey upon 

 everything that came within their reach, man}- of them, when 

 the earth became peopled with the higher animals and over- 

 grown with the plants for which their activities had prepared 

 the way, turned upon these usurpers and sought their 

 annihilation. These microscopic beings of the underground 

 world are the bacteria, moulds, fungi, blue-green algae, myxo- 

 mycetes and the host of dreaded germs which plague us, our 

 cattle and our crops. 



The main work of these organisms, however, is not to cause 

 disease in the higher animals and plants. The soil is not 

 primarily a medium on which to grow trees and herbs but is 

 the domain in which bacteria and other lowly forms of life 

 exert their activity ; the higher plants exist by virtue of these, 

 just as animals live by virtue of the herbage. 



The lower organisms which live in the soil and belong 

 to the vegetable kingdom are usually divided into the bacteria 

 and true fungi, moulds, yeasts and so on. The following 



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