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SUMMARY: Bordelella pertussis incubated in liquid media is prevented from multiplying by autoclaved cysteine and is rapidly killed by another substance, possibly a peroxide. The inhibition by autoclaved cysteine is overcome by serum albumin and the inhibition by 'peroxide' is overcome by red blood corpuscles, haemin, or ferrous sulphate sterilized by filtration. In a medium containing casein hydrolysate and yeast extract, logarithmic growth may continue for a 5 0 hr. a t one rate and then may change to a slower rate which continues for a further 20-30 hr. before growth stops. The initial growth rate can be maintained throughout by adding high concentrations of whole blood. The yield of organisms is proportional to the concentration of glutamic acid up to 0.3 yo (w/v). It is possible that growth a t greater concentrations is stopped by the high pH value caused by the oxidation of glutamate. Omission of casein hydrolysate decreases the yield of bacteria. A larger yield is obtained by the use of a large inoculum of bacteria with adherent blood.

SUMMARY: Bordetella pertussis, B . parapertussis and B. bronchiseptica all grow in an amino acid medium, using glutamate and forming ammonia from it. After the glutamate has been used, B. pertussis and B. parapertussis deaminate aspartic acid, serine, glycine, alanine and proline. B . bronchiseptica, as well as these amino acids, deaminates threonine, valine, methionine, the leucines and phenylalanine, leaving only histidine, lysine and arginine. B. bronchiseptica grows the most rapidly of the three and B. pertussis the most slowly. AU three organisms oxidize glutamate to give CO, and ammonia but in each some nitrogen is unaccounted for. B. bronchiseplica contains a glutamic decarboxylase and B . parapertussis forms a pink pigment from tyrosine.The genus Hwmophilus originally contained organisms which required blood for growth. As the true requirements of the species were found, it became clear that blood was required by different members for different reasons. The influenzae-parainfluenzae-canis group needs haemin and coenzyme I , but

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