Journal 



OF THE 



NEW-YORK MICROSCOPICAL SOCIETY. 



Vol. II. NOVEMBER, 1886. No. 8. 



BACTERIA IN DRINKING-WATER. 



BY CHARLES E. PELLEW, M. E. 

 {Read March ibtk, 1886.) 



The question of a supply of pure drinking-water has been a 

 very important one for many hundreds of years. A command- 

 ment, and a very good one, among the ancient Egyptians was, 

 "Thou shalt not pollute thy river-supply." The ancient Ro- 

 mans, as we know, drew their supply of pure water from great 

 distances. Much attention was given during the middle ages to 

 the problem of furnishing cities with good potable water, less, 

 however, for private than for public uses. Within the last cen- 

 tury the belief that diseases may be disseminated through the 

 medium of polluted water, has attracted increased attention to 

 methods of obtaining pure water for drinking purposes. Among 

 the diseases so disseminated is typhoid fever. So cholera is 

 supposed to be spread ; likewise, other contagious diseases. It 

 is, therefore, important to the world at large as well as to scien- 

 tific people, that means be devised whereby pure water can be 

 distinguished from water which is impure. 



The chemist was the first to attempt this by analyzing water 

 after the simplest methods. A quantity of the water to be 

 tested was evaporated to dryness, and the residue was found to 

 consist partly of mineral matter — lime, potash, etc.; but the 

 healthfulness or unhealthfulness of the water tested was not 

 ascertained by this plan. The nitrogenous organic matter con- 

 tained in the water was next considered the disease-producing 

 element, and of late years the chemist has directed his analyses 

 toward determining what proportion of this matter, particularly 

 in the form of ammonia, the water examined by him contained. 



