SEA-FISHERIES LABORATORY. 69 



removal of over 95 per cent, of the sewage bacteria originally 

 contained in the shellfish. 



A practical working experiment was made at Overton 

 in the Estuary of the Lnne. Arrangements were also made 

 for the certification of the treated mussels. Similar experi- 

 ments on an industrial scale are being made at Aberdovey and 

 Barmouth, in anticipation of the confirmation of the Order now 

 being promoted by the Committee. It is important to notice 

 that sewage bacteria rapidly die out when they enter sea- 

 water. The various species, however, die out at different rates. 

 Some observations with regard to this matter also have been 

 made, and are reported on. 



Mussels which are contaminated by sewage contain a 

 number of different species of bacteria. Some of the latter 

 are not of dangerous significance, i.e., they may not have come 

 from the human alimentary canal ; others have this origin. 

 Most of these bacteria have hitherto been regarded somewhat 

 loosely as being " Bacillus coli," though Dr. Alfred McConkey 

 has shown that they ought not to be so confused. 

 Dr. Johnstone now gives details of the reactions of a large 

 number of bacteria isolated from sewage and, by applying 

 McConkey's methods of analysis, shows that there is a 

 considerable difference between the proportions of the various 

 species of micro-organisms present in mussels and those 

 present in human faecal matter. Probably most faecal 

 micro-organisms die out on entering sea-water. This matter 

 is obviously of great importance in regard to routine methods 

 of bacteriological analysis and deserves much more investiga- 

 tion ; but Dr. Johnstone's present paper will be found to be 

 a valuable contribution to our knowledge. 



Investigations on the Herring. 



Mr. Riddell reports on the measurements of a number of 

 variable characters of herrings made by him during 1914. 

 This investigation is part of a larger scheme promoted and 

 organised by the Board of Agriculture and Fisheries, and our 



