148 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



l/50th mussel. There were 257 and 418 red colonies on these 

 plates, thus showing a very considerable amount of reduction 

 of the contained bacteria. Ten colonies were selected from 

 the first plate, and pure subcultures were made. Nos. 1 to 9 

 gave the reactions : — Glucose, lactose and dulcite all + ; 

 cane sugar, acid ; adonite and inuline — ; indole + ; Vosges 

 and Proskauer's reaction — . No. 10 gave the same series 

 of reactions except that dulcite was not fermented. There 

 was thus, apparently, a slight change in the biological characters 

 of the organism, but without further confirmatory work of 

 the same kind one cannot positively assert that this change 

 is a real one. 



There remains the series of experiments already quoted. 

 A dulcite + organism isolated from faeces was inoculated 

 in sea-water and cultivated there for seven days. Then it 

 was recultivated on neutral red, bile-salt, lactose agar, and then 

 on nutrient agar. Ten colonies gave the original reactions. 

 The organism was again inoculated in sea-water and grown 

 there for three days, and again passed through neutral red and 

 nutrient agar. Eight colonies all gave the original series 

 of reactions. 



Thus no change in the characters of this organism was 

 produced by a rather long sojourn in sea- water. So far as 

 they go, these two experiments do not support the notion 

 that faecal micro-organisms undergo any change of biological 

 characters, when they enter sea-water or the alimentary 

 canals of marine shellfish. They die out, of course, but so 

 long as they live they exhibit their original powers of fermenting 

 carbohydrates. Of course the number of observations made 

 is far too few to serve as the basis for any general statement 

 with regard to this point. 



(5) Summary. 



(1) The process of self-cleansing of sewage polluted 

 shellfish by placing them for some days in sea-water, which 



