44 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS. 



work, therefore, the ability to demonstrate clearly the presence of a specific sewage 

 organism such as B. coli is an invaluable aid in determining the question of purity or 

 pollution." 



Fuller 23 concludes his work on oysters from the .N arragansett Bay 

 by saying : 



The results obtained in these experiments indicate that B. coli is not normally 

 found in sea water or in common edible shellfish, and that the presence ot this organism 

 in oysters, clams, mussels, and similar shellfish is an indication of sewage pollution. 



VITALITY OF BACILLUS COLI AND BACILLUS TYPHOSUS IN SEWAGE- 

 POLLUTED WATER AND IN SHELLFISH. 



The results obtained by different investigators on this point vary 

 somewhat according to the conditions under which the experiments 

 were conducted: the vital fact, however, is that B. coli, B. typhosus, 

 and other organisms do survive sufficiently long, under favorable 

 conditions, in sewage-polluted waters to transmit disease when such 

 water is consumed, whether directly, or indirectly by such a medium 

 as shellfish. 



Savage 59 says : 



Owing to the enormous difficulties inherent to the isolation of the typhoid bacillus 

 from bacteriologically complex substances such as highly polluted tidal mud it would 

 be rash to draw sweeping deductions from negative results, but * * * it seems 

 justifiable to infer that typhoid bacilli can survive in polluted muds for at least two 

 weeks, and this fairly readily, but that after about two weeks they may rapidly de- 

 crease, although they may, and probably do, persist under favorable conditions for 

 some little longer, but in vastly diminished numbers. Experiment (3) seems to 

 definitely show that they may survive for at least three weeks. 



McNaught 42 concludes that "the duration of life of B. coli in 

 unsterilized water varied greatly in waters from different sources. 

 The purer the water the longer did B. coli survive in it." He further 

 says: 



In unsterilized sewage B. coli only survived for three weeks, while it survived over 

 eight months in the same sewage sterilized. After six months' growth in sterilized 

 water and eight months' growth in sterilized sewage B. coli retained all its original 

 characters except that possibly its power of indol production was weakened. 



The Lancet, 37 in reviewing some experiments and observations 

 on the vitality of B. typliosus in oysters made by Klein, says: 



The actual results detailed in the report, though valuable, are not particularly novel. 

 They definitely settle the question as to whether the Bacillus typhosus will live in the 

 oysters. It is demonstrated that there is destruction of the Bacillus typhosus both in 

 the body of the oyster and in sea water; that an oyster infected with large numbers of 

 typhoid bacilli " cleans" itself in about from 9 to 12 days when placed in clean water 

 which is frequently changed; and that oysters kept in the dry state, though capable 

 of destroying the bacillus, yet remain polluted for a much longer period than oysters 

 placed in constantly changed clean water. 



The investigations of Dr. Buchan 10 show that typhoid bacilli sur- 

 vived in mussels for at least 26 days where the organisms were found 

 abundantly; he concludes by saying: "This experiment emphasizes 



