BIOCHEMICAL ACTIVITIES 797 



and dextrin ; no strain fermented mannitol or lactose ; 53 per cent, produced indole. 

 Of the 29 hsemolytic strains, all fermented dextrose and reduced nitrates, the majority 

 fermented maltose and saccharose, 3 fermented galactose, 10 Isevulose, and 15 dextrin ; 

 none fermented mannitol or lactose ; 3 produced indole ; and 4 formed gas. It would 

 appear that the hsemolytic, as compared with the non-hsemolytic strains, ferment maltose 

 and saccharose more frequently, galactose and Isevulose less frequently, and seldom produce 

 indole ; but the number of hsemolytic strains examined was small. StUlman and Bourn 

 specifically note that they obtained irregular results when they carried out repeated tests 

 on the same strains. Fildes (1924) notes that the hsemolytic strains studied by him fer- 

 mented glucose, saccharose, and maltose ; but not lactose, dulcitol, or mannitol. The non- 

 hsemolytic strains oi H.influenzcB which he examined did not ferment any of these sugars. 



Kristensen (1922) carried out a considerable number of fermentation tests, but obtained 

 almost entirely negative results. It seems probable that these were due to an unsatisfactory 

 technique. 



Dible (1924), using a technique which did not differ essentially from that employed 

 by Stillman and Bourn, obtained results which he regarded as sufficiently sharjj and constant 

 to afford a basis for a tentative grouping of his strains ; though he notes that, of 25 strains 

 which were retested after 8 months, 9 showed changes in their fermentation reactions. 

 In 8 cases this change involved a loss of the power to ferment one or more carbohydrates ; 

 in the remaining instance a strain, previously inactive, was found to ferment glucose. It 

 may be noted that, of 14 hsemolytic strains, 9 fermented glucose and Isevulose, none 

 galactose, 8 saccharose, and 6 maltose, while none formed indole. Of 6 non-hsemolytic 

 strains, which Dible excludes from the species H. influenzce on account of their bacillary 

 or thread-like morphology, 4 fermented glucose, 4 Isevulose, 5 galactose, 4 saccharose and 

 none maltose, while none produced indole. Of 45 strains which showed the typical minute 

 bacilli and cocco-bacilli, 38 fermented glucose, Isevulose and galactose, none fermented 

 saccharose or maltose, while 16 produced indole. Dible's results thus tend to confirm those 

 of Stillman and Bourn with regard to the frequency of saccharose fermentation, and 

 infrequsncy of indole formation, among the hsemolytic as compared with the non-hsemolytic 

 strains. 



In regard to the relation between morphology and fermentation reactions among the 

 non-hsemolytic strains. Smith (1931) records observations on 143 strains isolated from the 

 nasopharynx of normal persons. There was no clear-cut fermentative separation between 

 morphologically typical and atypical strains, but, in conformity with the results recorded 

 by other workers, it was found that the typical strains showed a more restricted enzymic 

 activity than the atypical. Thus, 22-6 per cent, of the atypicals fermented saccharose, as 

 compared with 4-3 per cent, of the typicals. The correlation between typical morphology and 

 abihty to form indole was further confirmed ; 63-9 per cent, of the cocco-bacillary strains 

 were indole-producers, as against 18-0 per cent, of the morphologically atypical strains. 



Later work with para-influenzal strains makes it clear that the hsemolytic influenzal 

 straijis referred to above and the strains isolated in an epidemic of pharyngitis by Laraont 

 (1926) had the biochemical reactions of H. para-influenzce. Miles and Gray (1938) found 

 that aU of 12 hsemolytic strains of this organism were alike in fermenting dextrose, Isevulose, 

 maltose and sucrose, and in producing no indole. The reaction of 9 non-hsemolytic strains 

 of H. para-influenzce were variable, though all fermented dextrose and sucrose and two 

 were rndole-positive. 



On the basis of haemolysin production, indole production and other fermentative 

 reactions, taken in conjunction with morpliology and dependence on the X and V 

 factors, we may, then, recognize several different types of H. influenzce. 



(1) Typical H. influenzce — requiring both X and V factors, showing a predomin- 

 antly cocco-bacillary morphology, not producing haemolysis, usually showing a 

 restricted range of enzymic activities, particularly in failing to ferment saccharose, 

 and usually producing indole. 



