264 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



in abundance can always be obtained here, and further 

 because it is a good distance (12 miles) from land, and 

 so fairly free from the influence of fresh water which 

 might contain sewage microbes. Nevertheless, we ex- 

 pected to find some traces of sewage bacteria here, since 

 the hoppers carrying dredged material from the Mersey 

 Docks deposit this not far from the lightship. Trawls or 

 dredges used here usually bring up broken earthenware 

 and other like debris. After several trials with a large 

 dredge we found plenty of oj^sters a mile or two South by 

 West of the ship, in five fathoms of water, and on a 

 gravelly bottom. About a dozen were brought back the 

 same evening and stored during the night in a large clean 

 glass vessel, standing in a large basin and surrounded by 

 broken ice. The primary inoculations were made early 

 next morning. The oysters were well scrubbed under the 

 tap and opened with a sterile oyster knife. They were 

 all large and very fat fish. The liquid in the pallial 

 cavity was then drained off; a crucial incision was made 

 through the visceral mass so as to open up the stomach 

 cavity, and from the liquid which filled up the cut so 

 made 025 cc. was withdrawn with a sterile pipette and 

 inoculated on the surface of neutral-red agar. An equal 

 quantity was also inoculated in milk tubes and incubated 

 aoa>robically in the usual manner. 



The results of the primary cultures were : — 



Oyster 1. — Sterile. 



„ 2. — One colony (colon-like). 



,, 3. — Sterile. 



,, 4. — One colon-like colony. 



„ 5. — Sterile. 



„ 6. — Sterile. 



The two colonies, both of them largo, red and rapidly 



