1902.] FARM SANITATION. 55 



If it passes through a portion of soil highly contaminated with 

 filth, it will dissolve a portion of such filth and hold other 

 portions in suspension, and so the ground w-ater is liable to 

 be polluted by the same filth as the soil through which it has 

 passed. 



Just here it is proper to call your attention to the dififer- 

 ence which results from the different ways of putting filth in 

 contact with the soil. If the filth is applied upon the surface 

 or only a few inches below the surface, not in masses nor in 

 excessive quantities, it will speedily be disposed of without 

 being in any way injurious to health or offensive to our 

 senses. A French scientist once filled a bottle with dry 

 erarden loam. He first made a little hole in the bottom of 

 the bottle. Then he slowly poured into the bottle a quantity 

 of very dark, bad-smelling effluent from a dung heap. After 

 a while it began to leak out through the little hole in the 

 bottom of the bottle, and he was much surprised to find it 

 free from odor and almost free from color. A remarkable 

 transformation had occurred in the offensive Hquid which he 

 had poured into the bottle. 



The State Board of Health of Massachusetts, by the ex- 

 periments on the purification of sewage which it has been 

 conducting for several years, has explained the mystery. All 

 organized matter which has been endowed with life, whether 

 animal or vegetable, eventually dies and the substance of 

 which it was composed becomes disorganized and resolved 

 into the original elements of which it consisted. It has been 

 determined that at the surface of the ground, where waste 

 material would most naturally be found, nature has provided 

 an army of scavengers, innumerable in number and micro- 

 scopic in size. They inhabit the few inches of the soil imme- 

 diately below the top, where some degree of light and the 

 atmosphere can penetrate. 



They are some of the many forms of bacteria. They seize 

 promptly upon all dead organic matter and disintegrate and 

 tear its constituent elements apart, using such as they need 

 for their own maintenance and setting free the rest in such 

 forms as to be available for the use of other living things, 

 that is, as food for new organizations. 



Under these conditions decomposition of organic matter 

 takes place inoffensively and practically without soil pollu- 



