148 Physiology. 



Abolish the Cesspool. It is better and safer to have 

 no cesspool. Where a sewer system is not to be had, it is 

 better to allow no great accumulation of such material. A 

 deep pit in which a quantity of semiliquid matter gathers 

 is not only a nuisance but a source of danger. Privies 

 should have a very shallow pit, or none, and should be 

 cleaned often. There should be a little dust sprinkled in 

 each day, and occasionally some chlorid of lime or sulphate 

 of iron. 



Typhoid Fever. Typhoid fever is usually caused by 

 drinking-water. The excretions of some one who has had 

 the disease find their way into the source of the drinking- 

 water. In many cases this has been clearly proved. Of 

 course the excretions of all such patients should -be either 

 destroyed or thoroughly disinfected. 



Ice Water. Although bacteria will not develop in a 

 cold place, they are not killed when frozen in water, as 

 was formerly supposed. Further, ice, in forming, does 

 not throw out all the impurities, as was formerly believed. 

 So it is not safe to drink water formed from melted ice 

 unless the water of which that ice was made was good 

 water. The ice taken from ponds is not safe. If ice is 

 made artificially from suitable drinking-water, the melted 

 product will be essentially unchanged so far as the com- 

 position is concerned. Water may be cooled by placing 

 any ice around it, and we may have the desired tempera- 

 ture without danger. 



Boiling Water. When one cannot get good drinking- 

 water, or when away from home where the water is of 

 doubtful purity, it is better to boil the water before using 

 it, either as a drink or in preparations of food that are not 

 to be thoroughly cooked. It seems to be proved that it is 



