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Bacterium the colonies of which acquire colour on exposure to light, particularly certain of the mycobacteria in which the feature is an aid to identification. Certain microorganisms in which a pigment develops when it is grown in the presence of light, such as Mycobacterium kansasii.  

General diluent in microbiology, 0.8 per cent aqueous sodium chloride containing 0.034 per cent potassium dihydrogen phosphate and 0.121 per cent dipotassium hydrogen phosphate.  

The detection of Staphylococcus pyogenes colonies by their growth on agar containing phenolphthalein phosphate. Coagulase-positive staphylococci produce phosphatase which liberates phenolphthalein from the medium. Colonies of staphylococci which have released the indicator are then apparent when exposed to ammonia vapour.  

Characterization test of the ability of an enterobacterium to deaminate phenylalanine to phenylpyruvic acid a property peculiar to the Proteus md Providencia species. Performed by adding ferric chloride to a culture in buffered DL-phenylalanine, green colour indicating positivity. The phenylalanine may be included in a yeast extract agar or alternatively in malonate – phenylalanine fluid…

Acid-resistant penicillins and hence suitable for oral administration. Listed as phenethicillin, propicillin and phenbenicillin.  

The demonstration of in vivo bacteriolysis by the injection of cholera vibrios into a guinea-pig, together with anti-cholera serum devoid of complement. Withdrawn peritoneal fluid shows progressive lysis of the vibrios, due to the action of the antiserum plus the animal’s own complement.  

Treatment of sputum or other biological material with 4 per cent sodium hydroxide to kill bacteria other than mycobacteria. After 20-30 minutes’ exposure the material is centrifuged, neutralized, smeared and planted on egg or other media adapted to the growth of mycobacteria, especially tuberculosis.  

Flat circular plates 214-6 inches in diameter with a wall of 3/8 inch, made in pairs, one being slightly greater in size and forming a lid for the smaller plate, into which melted culture medium is poured and allowed to set. Petri dishes may be of glass (sterilized by heat) or transparent plastic material (sterilized…

Wire the terminal inch of which is bent at an angle, and carries the cotton-wool swab. Used for swabbing the nasopharyngeal space—in whooping cough, and for the detection of carriers of the meningococcus.  

Culture medium (and base for addition of fermentable carbohydrates) consisting of peptone, sodium chloride and water. Agar may be added.