84 THE SPIRIT OF THE SOIL 



usually adopted, a laboratory-performed change is 

 frequently more effective for a given purpose than 

 one carried out under natural conditions. In the 

 present case, for instance, if the peat were simply 

 thrown upon sandy soil, enormous quantities of it 

 would be lost. Much of the valuable soluble humus 

 would be leached out by rain, and pass deep into the 

 sand, or be wasted so far as the farmer is concerned 

 by being carried off in the drains. In the laboratory 

 and factory, however, it is a simple matter to control 

 the air-supply and the temperature so as to give 

 the aerobic bacteria the conditions under which they 

 can work best. Only the inevitable amount of 

 Carbon dioxide is given off and wasted. The process 

 throughout the mass is homogeneous, and the 

 reaction carried to the exact conclusion desired. 



In such conditions the results obtained are amaz- 

 ing. In this connection there can be no question 

 as to the result, for it can be tested as often as the 

 observer cares with the greatest ease in any labora- 

 tory, no elaborate appliances or delay being involved. 

 All that is required is half a dozen test-tubes, a 

 couple of filters, and a little Hydrochloric acid, 

 some well-rotted stable manure, and samples of 

 treated and untreated peat. The value of the 

 rotted stable manure lies in its soluble content, and 

 the amount of it is easily gauged approximately by 

 the eye and accurately by the balance. Supposing 

 that equal weights of rotted stable manure, raw 

 peat, and treated peat are taken, well steeped with 

 equal volumes of water and filtered, the liquid from 

 the untreated peat is found to be almost colourless, 



