152 PHYSIOLOGY. 



proved. Of course the dejecta 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 water freezes, as was 

 formerly supposed. Further, ice, in forming, does not 

 throw out all the impurities, as was formerly stated. 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, of course the 

 melted product will be essentially unchanged so far as the 

 composition is concerned. Water may be cooled by plac- 

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

 perature without any admixture of a dangerous element. 



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 better to heat the water twice nearly to the boiling point 

 than to boil hard once only. The first heating may start 

 the resistant germs into more active life, causing them to 

 sprout (so to speak), and a second heating several hours 

 later may easily kill them ; whereas it has been proved 

 that one hard boiling will not always kill the germs. 



Cautions as to Drinking Water. Or if one uses tea 

 and coffee, it is safer to content one's self with these, and 

 not drink much water till that which is safe, as from deep 

 wells, can be obtained. 



In hot weather, and especially for those who are engaged 

 in hard work, it has been found that a little oatmeal 

 stirred in the water is beneficial. 



