[Search for the systems of DNA host specificity in Salmonella typhi].
Seventeen pure lines of S. typhi bacteriophages have been obtained from mother races O and Vi; of these, three were used to study 152 S. typhi strains with a view of detecting their DNA host specificity systems. 10 S. typhi strains having the DNA host specificity system have been detected by the rough determination of the lytic spectrum and the cross titration of phage Vi IX.