ISOLATION OF THE COLON BACILLUS. 69 



make confident use of the practical test. It is, of course, 

 highly desirable that some standard set of reactions 

 should be commonly adopted by sanitary bacteriologists; 

 and it is to be hoped that some such uniform scheme may 

 soon be drawn up by the Society of American Bacteriolo- 

 gists or by the American Public Health Association. At 

 present the plan developed by the Massachusetts State 

 Board of Health (Massachusetts State Board of Health, 

 1899) is most widely prevalent in this country. It in- 

 volves the use of six simple, definite, positive tests — the 

 growth in gelatin, lactose-agar, dextrose broth, milk, 

 nitrate solution, and peptone solution. 



For recording the results of the various tests applied, 

 the appended blank form has been in use at the Massa- 

 chusetts Institute of Technology. On the upper part of 

 the sheet are noted the results of the gelatin count and 

 the litmus-agar count at 37 . In the second case the 

 number of acid-formers is placed in brackets after the 

 total numbers. The lower Dart is used for the B. coli 

 isolation. 



MASSACHUSETTS INSTITUTE OF TECHNOLOGY. 

 Bacteriological Examination of Water. 

 Sample No. Date of collection 



Examined by Hour of collection 



Place of collection Remarks 



