ACtlNOMYCOSiS 321 



it occasionally occurs in long forms and filaments ; it is non-motile, 

 non-liquefying, and has no spores; it does not stain by Gram's 

 method, which stain is therefore used for differential diagnosis ; it will 

 grow fairly well in ordinary gelatine at 20 C. ; and it is a denitrifying 

 organism, and also an actively fermentative one, even fermenting 

 glycerine. It is not unlike B. coli communis, and to distinguish it from 

 that organism it should be remembered that the B. coli is motile, 

 never has a capsule, produces indol, and does not ferment glycerine. 



It is now generally held that Frankel's diplococcus is the chief 

 factor in the causation of croupous pneumonia, and probably plays 

 an important part in other forms of the disease. In the septic 

 pneumonias the different suppurative organisms are found, and some- 

 times in ordinary pneumonias these organisms may be the causal 

 agents. 



Influenza 



In 1892, during the pandemic of influenza, Pfeiffer dis- 

 covered a bacillus in the bronchial mucus of patients suffering 

 from the disease. It is one of the smallest bacilli known, and 

 frequently occurs in chains not unlike a streptococcus. Canon 

 obtained the same organism from the blood. In the bronchial 

 expectoration it can retain its virulence for as long as a fortnight, 

 but it is quickly destroyed by drying. The bacillus is aerobic, non- 

 rnotile, and up to the present spores have not been found. It is 

 non-motile, and does not stain by Gram's method. It has no 

 capsule. It grows somewhat feebly in artificial media, and readily 

 dies out. Blood serum, glycerine agar, blood agar, and gelatine have 

 all been used at blood-heat. It does not grow at room temperature. 

 On blood agar colonies appear in twenty-four hours in the form 

 of minute circular dots, almost transparent. The bacilli die out 

 quickly in cultures. Pfeiffer's bacillus appears most abundantly at 

 the height of the disease, and disappears with convalescence. It is 

 said not to appear in any other disease. It is chiefly found in the 

 respiratory passages in cases of influenza, and is usually isolated from 

 nasal secretion and the masses of greenish-yellow bronchial sputum. 

 The bacilli may persist after recovery of the patient. 



Actinomycosis 



This disease affects both animals and man. As Professor 

 Crookshank has pointed out, it has long been known in this 

 country, but its various manifestations have been mistaken for 

 other diseases or have received popular names.* 



* Bacteriology and Infective 'Diseases (1896), pp. 413-447. Professor Crookshank's 

 Reports to the Agricultural Department of the Privy Council constitute a most 

 complete account of this disease. See also Trans. Jenner Institute (Second Series), 

 1899, p. 17. 



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