38 



They all come from animal and vegetable matter dissolved in the 

 water, and show the stages of decomposition which such matter has 

 reached. These stages depend upon the character of the soil and 

 the amount of contamination. 



Free and albuminoid ammonias are usually high where the 

 soil either permits free pollution or hinders the oxidation of the 

 organic matter. Nitrates are high when the soil favors the rapid 

 oxidation of the organic matter. Consequently, waters containing 

 much free and albuminoid ammonia arising from sewage, would 

 be dangerous ; but if the nitrogen were present only in the form of 

 nitrates, the sewage would have been oxidized to harmless mineral 

 matter. Nitrites being an intermediate stage in the destruction of 

 organic matter are looked upon as suspicious constituents of water 

 if not dangerous. (N. H. C. B. 53.) 



Care of Water. It should be borne in mind that the well on 

 any farm or any door-yard, cannot receive too much attention, for it 

 supplies the water for household use, and on the dairy farm, for 

 cheese factories, and for other purposes which are related to food 

 supplies. Well water is most commonly contaminated in two ways; 

 either by surface water running directly into the well, or by barn- 

 yard drainage, household slops, and cesspools. Sewage disposal may 

 be so managed that it is not a menace to the water supply ; one of 

 the most satisfactory methods is by the employment or use of a 

 septic tank, and this need not involve any great trouble or expense. 



In many instances, reasonable care of the surroundings of the 

 well would remove all danger from disease by the pollution of the 

 water. Privy-vaults should be made water-tight, well ventilated, and 

 frequently supplied with dry earth. Nature has provided abun- 

 dance of micro-organisms in feces and in soil that with plenty of 

 air and little moisture will rapidly change all soluble organic matter 

 into harmless gases to be dissipated in the atmosphere. The sink- 

 drain should be carried as far as practicable from the house to a 

 lower level than the bottom of the well if possible, and discharged 

 upon the surface of the ground. The sun will help disinfect the 

 sewage and if rank plants are encouraged to grow on the spot during 

 the summer, there will be little percolation to the ground-water. 



A cess-pool should never be used in the vicinity of any well 

 or spring ; a pit in the earth, from which the water, saturated with 

 soluble filth, slowly seeps away, furnishes practically no chance for 

 the purification by the soil organisms, because they act weakly or 

 not at all, at depths of two to three yards below the surface of the 

 earth. The economical handling of manure and garbage by com- 

 posting in cemented cellars or sheds, where leachings cannot escape, 

 will prove both pecuniarily and healthfully superior to the careless 

 treatment usually given those substances. 



On many farms a supply of water can be obtained from a 

 source remote from any danger of contamination, and the substi- 

 tution of such a source for the farm-well is the best means of receiv- 

 ing good water. When a spring is lower than the farm-buildings, 

 careful attention should be paid to the direction in which the drain- 



