^48 EGYPTIAN AGRICL'r/riRE. 



are micro-organisms which exist in immense numbers 

 and in great variety, the net result of whose actions is a 

 partial breaking up of the complex organic substances into 

 simpler forms. The exact nature of the changes which 

 result as well as the rate at which they take place depends 

 on a great many circumstances. In the first place the 

 higher the temperature, the more rapidly does decay take 

 place. Consequently, from this point of view, manure in hot 

 and semi-tropical countries will ferment more quickly than 

 in colder climates. Again, as fermentation is largely de- 

 pendent on the action of organisms which require oxygen 

 for their actions, the greater the surface exposed to the 

 atmosphere and the more loose the heap the more rapidly 

 will the manure decay. Decay is largely a process of 

 oxidation and though in a heap of manure, organisms are 

 found that can live in the absence of air, yet, it is through 

 the action of that class that can only live in its presence 

 that the final products of decomposition are chiefly formed. 

 The common practice of throwing farm -yard manure 

 into small or more or less scattered heaps, covering a large 

 space, which is prevalent in Egypt is not one to be recom- 

 mended. When carted from the stable and thus loosely 

 exposed to the sun and wind, there is a very rapid drying 

 and considerable loss of valuable nitrogen. As the manure 

 is removed almost daily, and not allowed to accumulate 

 under the animals to the same extent as is often practise! 

 in Europe, the urine (which as already mentioned contains 

 the bulk of nitrogen) is undergoing fermentation and 

 the products of the change are to a considerable extent 

 lost, largely in the form of the volatile carbonate of 



