308 Bacteria in Relation to Country Life 



creted in the milk and retained in the body may amount 

 to about one-sixth of the food-nitrogen. A portion of 

 the phosphoric acid and of the potash are also retained 

 in the body or secreted in the milk, although, in the case 

 of the potash, the portion retained is quite slight. Be- 

 cause of this destruction or retention of the food con- 

 stituents in the animal body, the amount of plant-food 

 in the manure is less than that in the food from which 

 it is produced. 



Other causes for losses. — The loss of plant-food con- 

 stituents does not stop here, however. Further losses 

 occur in the manure itself. These are brought about, 

 on the one hand, by the leaching of the soluble com- 

 pounds of nitrogen and potash, and to a slight extent, 

 also, of phosphoric acid from the manure pile, and on 

 the other, by various fermentations that lead to the 

 breaking down of the organic matter and the setting 

 free of nitrogen either in an uncombined state or as 

 ammonia. 



The monetary value of the plant-food leached out 

 from improperly stored manure is truly enormous. 

 The losses thus incurred are not directly due to bacterial 

 activities. However, the losses occasioned in the de- 

 composition of manure by bacteria are considerable, 

 but they concern only the organic matter and the nitro- 

 gen. The phosphoric acid and the potash are not changed 

 into gaseous products in the course of decay and cannot, 

 therefore, be lost when the manure is properly protected 

 from the leaching action of rain. 



Importance of proper storing. — The quality of organic 

 matter lost from the manure pile in the course of fer- 



