Published online by Cambridge University Press: 15 May 2009
1. The causes of failure of the brilliant green enrichment method for isolation of B. typhosus are discussed.
2. It has been shown that the negative results obtained depend partly on the number of resistant B. coli strains normally present in faeces, and partly on the use of McConkey's as a plating out medium.
3. The alleged selective action of telluric acid could not be confirmed.
4. The so-called antagonism between B. coli and B. typhosus has been investigated, and by the use of a selective bismuth medium it is shown that this is more apparent than real in most cases.
5. However, the existence of certain strains of B. coli or similar bacteria with a specific inhibitory effect on B. typhosus has been confirmed.
6. The value of Wilson's bismuth medium for the isolation of B. typhosus has been demonstrated.