QUALITATIVE DETERMINATIONS 91 



of the presence of intestinal parasites, such as the segments of tape 

 worm, the larvae and ova of such parasites, etc., as already stated 

 under the discussion of the direct method of making counts. The 

 bacteriologists in food and drugs laboratories should be qualified 

 to recognize all of the possible disease germs and the smaller carriers 

 of disease which may be associated with food substances and they 

 should be able to demonstrate the presence of such contamination, 

 if necessary. The thus far recognized routine in food and drugs 

 laboratories and in public health laboratories is limited to making 

 the so-called presumptive colon bacillus test, as indicative of sewage 

 contamination or contamination with fecal matter. Sewage con- 

 tamination means primary contamination with fecal matter. The 

 reason why the colon bacillus test has been selected as giving satis- 

 factory evidence of sewage contamination is because this bacillus 

 is most abundant and is constantly present in fecal matter. Any 

 considerable number of colon bacilli in water supplies or in food 

 substances is evidence of gross negligence and defects as to sanitary 

 requirements. 



As far as the practical work in finding evidence of the sewage 

 contamination of food substances is concerned, there is no effort 

 made to isolate and identify a definite bacillus recognizable as 

 Bacillus coli. It is rather the recognition of certain cultural 

 characteristics which have come to be recognized as being peculiar 

 to the bacilli, known as the B. coli group, all of which are traceable 

 to intestinal origin. Furthermore this group of bacteria is very 

 widely distributed in the animal kingdom, being in no wise limited 

 to the intestinal tract of man. The B. coli group of the lower 

 animals is in all probability different from that which inhabits 

 man and certain workers have made attempts to differentiate 

 them by means of special cultural methods, but thus far these 

 methods are not sufficiently perfected to be used practically in 

 food and drugs laboratories. These statements also apply to the 

 Streptococci group of intestinal origin. However, some of the 

 laboratory results thus far attained would indicate that in the 



