BACTERIA AND RURAL WATER SUPPLIES 3 



The next logical step for scientists was to try to develop methods for detecting 

 the presence of dangerous bacteria in water, milk, and foods. Results were not 

 encouraging so far as methods for routine use were concerned, so investigators 

 turned next to the development of methods which would indicate the existence 

 of conditions capable of spreading infections. What we now know as the various 

 "Standard Methods" are the outgrowth of these activities. 



The first step towards standardizing the bacteriological testing of water was 

 taken by the American Public Health Association in 1894, and as a result a 

 convention of American bacteriologists, in 1895, appointed a committee "to 

 draw up procedures for the study of bacteria (in water) in a uniform manner." 

 This committee's report was published in 1898 and served as a guide for the 

 testing of water supplies until the publication, in 1904, of the first edition of the 

 "Standard Methods of Water Analysis," compiled by a committee of the American 

 Public Health Association collaborating with other bacteriologists. The first 

 edition of the "Standard Methods of Milk Analysis" was published in 1910. 

 Both publications included chemical as well as bacteriological tests. Since then, 

 "Standard Methods" have been developed for the examination of shellfish and 

 various other kinds of foods, for detection of food poisoning, for evaluation of 

 methods of cleaning eating and drinking utensils, and for a number of other 

 purposes. 



In the development of standard methods, it is necessary that they be spon- 

 sored by some organization large enough, and well enough established and re- 

 garded, to give authority to their recommendations. The American Public 

 Health Association is such an organization in America. In some instances other 

 organizations in a particular field collaborate with the Association. The "Stan- 

 dard Methods of Water Analysis" is prepared and published jointly by the 

 American Public Health Association and the American Water Works Association. 

 It is fortunate that these organizations are not political and have no authority 

 to require the adoption and use of their methods. Health authorities in general 

 recognize the desirability of employing uniform laboratory procedures so that 

 results in different places can be compared and standards of quality to be met 

 by supplies of milk, water, and other substances can be made uniform. Con- 

 sequently, the "Standard Methods," particularly those for the testing of milk 

 and water, have been generally adopted over the country by municipal and state 

 legislation. 



Standard methods for any purpose are necessarily arbitrary. There is usually 

 more than one way to do anything, and there are likely to be differences of 

 opinion as to which of several procedures is better or best. In establishing a 

 standard method, efforts are made to simplify something which usually is quite 

 complex. No simple method devised for bacterio'ogical purposes can tell more 

 than a part of the story. No single medium can detect all of the types of bacteria 

 present in water or milk, for instance; the employment of one temperature for 

 incubation of cultures will fail to produce growth of bacterial sp^ecies that prefer 

 another temperature; the acidity or alkalinity of a medium will stimulate growth 

 of some types of bacteria at the expense of others; if materials such as dyes are 

 added to a medium to select certain species of bacteria, it naturally follows that 

 growth of others is prevented. 



Standard methods, to be most effective, should be employed and their results 

 interpreted by technicians who are well educated in science and know the values 

 and limitations of the methods. Unfortunately, that too often is not the case. 

 Many technicians in small municipal laboratories, and sometimes in industrial 



