120 BACTERIOLOGICAL EXAMINATION OF WATER. 



Gelatine-stab at 22 C. White thick growth on the surface 

 and along the stab ; later the growth acquired a light yellow 

 colour, and the gelatine slowly liquefied. 



Staining Reactions. Stained by Gram's method. 



Microscopical Characters. Large cocci in masses and in pairs ; 

 no chains observed. 



This organism appeared to be closely allied to the Staphylo- 

 coccus citreus. 



As a result of my experiments, I arrived at the conclusion 

 that streptococci presenting the above characteristics might 

 be extremely useful to the water-bacteriologist ; for if they 

 were found in the absence of B. coli, they would probably 

 indicate pollution of the water-supply by old sewage. 



Houston, however, is inclined to regard streptococci as 

 indicating recent and objectionable pollution. He states that 

 streptococci " as a class may be thought of as germs especially 

 liable to discouragement by unfavourable physical conditions ; 

 and, indeed, as surviving only when the conditions are almost 

 ideally propitious. In the present state of our knowledge, 

 therefore, the presence of streptococci in a substance, be it soil 

 or sewage or water, suggests recent association of certain 

 ingredients of that substance with an animal host. 1 ' The 

 following descriptions of streptococci, which were isolated 

 from water, are given to show the characteristics of the 

 organisms described by Houston. 



Streptococcus I 9 . Surface Colonies on Gelatine Plates. 

 Yellowish-grey, transparent, showing wavy granulation, edge 

 sinuous, and made up of loops of streptococci. No lique- 

 faction. Surface-agar Plates. Yellowish-brown, semi-trans- 

 parent colonies of irregular shape and small size. The chains 

 of cocci give the colonies a wavy, granulated appearance. The 

 loops of cocci are readily seen at the periphery. Broth. 

 Clear ; at foot of tube there are woolly masses, which tend to 

 cohere, and are somewhat viscous. Litmus-mill:. Practically 

 no change even after six days. Gelatine-slope. Trans- 

 parent coarsely granular colonies, which tend to remain 

 separate and not form a continuous growth. No liquefaction. 

 Morphology. Stains with Gram. Long chains of cocci ; also 

 masses made up of chains. 



