SEA-FISHERIES LABORATORY. 477 



Conway Estuary. 



26 June, 1909. 



A sample of mussels taken quite close to Deganwy 

 Sewer outfall. 



Five mussels emulsified in sterile water and made 

 up to a volume of 250 c.c. 



1 c.c. of the emulsion = 



(0-02 mussel) contained 25 intestinal* bacteria (also 55 colourless bacteria). 



62 

 Mean No. of intestinal bacteria per mussel = 2150. 



9 August, 1912. 



A sample of mussels from the bottom of the river 

 near the north side of the bridge. 



Five mussels emulsified in 250 c.c. of sterile water. 



1 c.c. of the emulsion = 



(0-02 mussel) contained 29 intestinal bacteria (No colourless bacteria). 



59 



33 



55 

 Mean No. of intestinal bacteria per mussel = 2200. 



9 August, 1912. 



A sample of mussels from the bight between Morfa 

 Parade and the point of land to the north-west. (Locally, 

 (Anglice) " Stinking Pool.") 



Five mussels emulsified in 250 c.c. of sterile water. 

 1 c.c. of emulsion = 



(0-02 mussel) contained 28 intestinal bacteria (1 plate contained about 50 



colourless bacteria). 



20 



40 



18 



Mean No. of intestinal bacteria per mussel = 1300. 



Water Analyses. — The small figures placed in the 

 chart on the Estuary at low water indicate the numbers 



* I call these bacteria isolated in Griinbaum's neutral-red, bile-salt, 

 lactose agar medium " intestinal bacteria " with all the reservations indica- 

 ted in my general discussion of methods of analysis. 



