BACTERIUM PNEUMOSINTES 899 



agar the colonies of some strains are surrounded by a faii-ly wide zone of incomplete 

 haemolysis, though no soluble hsemolysin is formed in fluid media (Oag 1942). On Dorset 

 egg low convex colonies are formed, which lead in a few days to slight pitting of the surface . 

 There is no growth on MacConkey agar. In serum broth after 24 hours at 37° C, there is 

 a uniform turbidity ; later a greyish- white deposit appears, and increases for 6 to 10 days, 

 after which the medium clears, the whole of the growth sinking to the bottom of the tube. 



Resistance, Biochemical Reactions, and Pathogenicity. — Cultures in serum broth 

 live for weeks at 35° C, but die in 48 hours if left at room temperature. The bacillus 

 is killed by moist heat at 58° C. in 15 minutes, and is apparently very susceptible to zinc 

 salts, which have an almost specific action in the treatment of angular conjunctivitis. 

 In our experience no sugars are fermented. Gelatin may be Uquefied, and Utmus milk 

 becomes very slowly alkaUne, though according to Oag (1942) acid is produced. Nitrates 

 are reduced. Catalase is negative. No indole is formed in serum broth cultures, even 

 after 7 days. According to Oag (1942) antigenic differences can be demonstrated by 

 agglutination between hsemolytic and non-hsemolytic strains. The organism is non- 

 pathogenic to laboratory animals, whether inoculated into the conjunctival sac or directly 

 into the tissues ; but a drop of culture instilled into the conjunctival sac of a healthy 

 human volunteer gives rise in about 5 days to a typical attack of angular conjunctivitis. 



A similar organism, B. duplex, was described by Petit in 1900, who isolated it from 

 cases of conjunctivitis associated with corneal ulceration. It differs from the Morax- 

 Axenfeld baciUus mainly in its abiUty to grow on media without the addition of natural 

 animal protein (though no growth may occur in ordinary broth), in its development at 

 room temperature, in its liquefaction of gelatin, and in its more active digestion of Loeffler's 

 serum, which it hquefies in 3 or 4 days. It is also said to be antigenicaUy distinct (Audureau 

 1940). On ascitic agar it gives rise to convex, not umbonate, colonies, which are greyish 

 in colour, viscous, and not so translucent as those of the Morax-Axenfeld baciUus. 



Another organism, which is closely related to, if not identical with, the Morax-Axenfeld 

 bacillus, was isolated by Jones and Little (1923) from cattle suffering from acute con- 

 unctivitis, sometimes compUcated by corneal ulceration. It is said to liquefy gelatin, 

 and to produce alkali in Utmus mUk. 



Classification. — The classification of these organisms is still in doubt (see Chapter 33). 

 Lwoff (1939) suggested that they should be groujied in a new genus, called Moraxella. 

 Audureau (1940) accepts this suggestion and recognizes three main species, lacunata, 

 duplex and Iwoffi. Moraxella lacunata grows only in the presence of serum ; Moraxella 

 duplex grows in the absence of serum but not in synthetic media ; and Moraxella Iwoffi, 

 which was isolated by Audui'eau from patients affected with conjunctivitis, will grow in 

 a synthetic medium free from protein and amino-acids, provided a little carbohydrate 

 is added to provide energy. 



Bacterium pneumosiutes. 



Isolated by Olitsky and Gates (1921a, h, c, 1922a, b) from the nasopharjTigeal washings 

 of patients in the early stage of influenza, and since observed by certain other workers 

 (Hall 1926). It is a very small organism and is capable of passing through Berkefeld 

 N and V candles. 



Morphology.- — In Smith-Noguchi medium on first isolation, it is described as con- 

 sisting of minute bodies, arranged singly, in pairs, or short chains ; its length is given 

 as 0-15-0-3 [x, and its breadth as two or three times less. After subculture for some 

 time in the laboratory, the organisms appear in dextrose peptone broth as plump rods 

 with rather pointed ends, arranged in pairs end-to-end, and in fairly long chains. It 

 may be 0-5-1 -0 n long ; it stains more deeply in the middle than at the ends. Our own 

 observations on one of Ohtsky and Gates's original strains, grown anaerobically for 12 



