264 BACTERIA IN OTHER FOODS 



the edible shell-fish within the area of sewage contamination showed 

 by the presence of virulent B. coli excremental pollution, and their 

 consumption must therefore be regarded as highly prejudicial to 

 health. Cultures of the species of B. coli killed guinea-pigs within 

 eighteen hours. (2) The shell-fish beyond the range of sewage 

 contamination were found to be normal and perfectly safe for edible 

 purposes. (3) Certain shell-fish, cockles and " muscins " (My a 

 arenaria) within the area of sewage contamination showed, accord- 

 ing to Buchanan, the presence of the bacillus of typhoid fever in 

 great number, and in some cases almost in pure culture, and the 

 consumption of similarly infected shell -fish by holiday visitors in 

 the end of July would sufficiently explain the outbreak of typhoid 

 fever which occurred amongst them after return to their own homes 

 in Glasgow and elsewhere. 



As regards the specificity of this bacillus, Buchanan reports that 

 it had all the microscopical and cultural characteristics of the 

 typhoid bacillus. Further, it gave the characteristic reaction with 

 human typhoid serum and with serum obtained from a typhoid 

 immunised guinea-pig. The finding of this bacillus in such numbers, 

 and in so many individual shell-fish, is so exceptional that it was 

 repeatedly subjected to reliable culture tests and to repeated serum 

 tests, and always with the result of proving its general identity with 

 the typhoid bacillus obtained from a case of typhoid fever. 



A third apparent instance of finding the typhoid bacillus may 

 be quoted. In 1902-1903 Klein examined ten samples of Leigh 

 cockles, and found every one of them showing evidence of sewage 

 pollution, though six had been " cooked." One of the uncooked ones 

 contained B. typhosus, a typical typhoid bacillus agglutinating with 

 typhoid blood (Klein). The cooking to which some of these cockles 

 were submitted must have been perfunctory, as it is fairly well estab- 

 lished that 60-61 C. kills B. coli. Yet this organism was found in 

 two instances where the cockles in question had been "boiled con- 

 tinuously for one minute," or " put in boiling water and taken out 

 when the water boiled over, time in water three and a quarter 

 minutes." * 



These facts reflect a new and not reassuring light upon the 

 possibility of cockle infection. But they must be accepted with 

 great reserve until very fully confirmed. Dr Bulstrode in his report 

 on Oyster Culture in 1896 suggested that the infection by cockles 

 was a remote contingency, because " in the first place these molluscs 

 are, as a rule, only eaten after being cooked ; and in the second place 

 it is seldom that extensive cockle industries are carried on in other 

 localities than those where large stretches of sand are exposed at 

 low tide, and such stretches are found chiefly on the actual seashore 

 * Report of Medical Officer of Health of City of London, 1902, pp. 134-149, 



