248 Microbes and You 



grown on such farms. In China and in other countries where 

 fertihzers are scarce, it is routine practice to save human excre- 

 ment and use it for fertihzer. Such material is termed night soil. 

 Undoubtedly a great number of pathogenic microorganisms are 

 transmitted to humans by this practice. 



Overloading bodies of water with excessive quantities of or- 

 ganic matter lowers the concentration of dissolved oxygen, and 

 this endangers fish life. The effluent from sewage disposal plants 

 should be treated to remove organic matter before dumping the 

 wastes into streams, rivers, or lakes. State Water Commissions 

 are constantly faced with the problem of controlling pollution of 

 water, and their efforts are beginning to bear fruit. 



Pollution of water near public bathing beaches has become in- 

 creasingly serious in recent years, with pollution reaching such 

 proportions that health authorities in some localities have been 

 forced to close specified areas for human bathing. Shellfish 

 gathered in these locations have spread typhoid and other enteric 

 diseases when the food has been consumed without proper cooking. 

 While sewage has been shown to contain the virus of poliomyelitis, 

 no one has conclusively demonstrated that this disease is trans- 

 mitted through bathing in such polluted water. Tuberculosis or- 

 ganisms can also be isolated from polluted water on occasion, but 

 this disease is not normally considered to be contracted by persons 

 bathing in such water. When authorities quarantine beaches at 

 the height of polio epidemics, the restriction is usually enforced 

 with the object of minimizing close contact of large numbers of 

 individuals. In general, this restriction is not enforced as a result 

 of fear that persons will ingest the virus from the contaminated 

 water. 



GARBAGE AND OTHER WASTES 



Edible food becomes garbage in one sweep of the arm when 

 plates are removed from the table. Garbage may be defined as 

 refuse animal or vegetable matter. Since this material is capable 

 of undergoing decomposition with accompanying foul odors, to 

 say nothing of its unsightly appearance, proper garbage disposal 

 is of extreme importance from the standpoints of human health. 



