46 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



draw their food supply from the country is in a measure dependent 

 upon the healthfulness of the farming community. In fact, there 

 is scarcely a city child whose health is not in a degree dependent 

 upon the sanitary condition of the barn and house of the dairyman. 

 Milk has frequently been shown to be the means of disease dis- 

 tribution. 



With these conditions before us it is aibsolutely necessary to 

 have a good sewage-disposal plant on every farm. Health cannot be 

 measured by cost; for a small cost should not stand in the way to 

 any great extent in erecting a plant that is effective for this purpose. 



The average cow voids about 20,000 pounds of manure per 

 year, of which approximately 9,500 pounds are liquid and 10,500 

 pounds solid. If the gutters are properly constructed the liquid 

 manure will take care of itself and will reduce the labor one-half, of 

 what it would be were the liquid absorbed by some absorbent like 

 straw and then removed with the solid excrements. 



Liquid manure contains a high per cent of nitrogen, the most 

 expensive part of a fertilizer. According to Snyder, liquid manure 

 from cows fed a well-balanced ration contains about 89 per cent 

 water and 1.2 per cent of nitrogen; solid manure contains 76 per 

 cent of water and .5 per cent of nitrogen. This shows the com- 

 parative high value of liquid manure, which, on average farms, is 

 allowed to flow into streams and pollute the same. 



According to Woll, the value of manure from a cow for one 

 year, fed on a well-balanced ration, is estimated at $29.97. This is 

 a source of income for the farmer which is seldom taken into con- 

 sideration because his conditions are such that he is not able to take 

 care of it. By means of a proper sewage-disposal system the value 

 of this manure may be fully recovered, besides making conditions 

 on the farm more sanitary. 



Manner of Disposing of Sewage. The disposal of sewage is 

 brought about by the decomposition of the organic matter. All 

 sewage is largely organic matter and water. All organic matter de- 

 cays. This decaying process is simply the disintegrating action of 

 minute organisms known as bacteria upon the solid parts of the 

 sewage, dividing the same into such a form that it becomes fluid. 

 The superficial layers of soil from six to twelve inches are thorough- 

 ly innoculated with bacteria. The action of the bacteria upon any 

 organic material is to reduce the complex organic compounds into 

 simpler compounds. Hence, decay is the destruction of complex 

 substances that have been built up by growth. There are certain 

 kinds of bacteria that can penetrate organic substances to a slight 

 extent only. Some must have air, particularly oxygen, to decay a 

 portion of the mass, while there are other bacteria that have the 

 power of decomposing organic material without the presence of air 

 or oxygen. In the system herein described it is chiefly the last kind 

 of bacteria with which we have to deal. The sewage discharges into 

 a receptacle that is air-tight, known as a septic tank. This sewage 

 is acted upon (by these bacteria, which partially decomposes and 

 liquefies the same. Most of the disagreeable odors are liberated by 



