V] METHODS OF INOCULATION 7; 



B. — Detection of Special Microbes by 

 Special Methods. 



Bacillus coli, being chiefly derived from the intestinal con- 

 tents of man and animals, would in the nature of things 

 occur in all matters : dust, earth, food-stuffs, mucous mem- 

 branes which have been exposed to pollution with matter 

 tainted with dejecta. Thus in large towns almost everything 

 is liable to become so polluted owing to the almost ubiqui- 

 tous presence of dust tainted with animal dejecta. The 

 same applies to any place and any material to which such 

 dejecta find access. This bacillus coli can, therefore, under 

 particular conditions of locality, be regarded as almost ubi- 

 quitous. The same applies to proteus vulgaris, but in a 

 somewhat more limited degree, since this organism, although 

 present in the alimentary canal, is nevertheless not so common 

 in this ; but being the chief organism producing the putrid 

 decomposition of albuminous substances, it will be found 

 wherever such substances undergo this change. These two 

 organisms or either, notably bacillus coli, if present in large 

 ninnbers in any water, would indicate that that water had been 

 subject to excremental pollution or that there exist in the 

 water putrid animal matter. A very limited number of bacillus 

 coli need not be and is not sufficient to condemn such water, 

 because the accession to it of a little dust, carried there by 

 air currents, originally impregnated with animal excreta, 

 would produce such a result, but in this case the bacillus 

 coli would in a large bulk of water be very scantily dis- 

 tributed. It is different if the bacillus coli or proteus vul- 

 garis, particularly the former, be present in large numbers, 

 for then pollution with excremental matter has probably 

 taken place. Take, for instance, water derived from deep 



