418 THE PNEUMOBACILLUS 



SECTION IV. DETECTION, ISOLATION AND IDENTIFICATION OF 

 THE PNEUMOBACILLUS. 



I. In sputum. (a) Prepare films and stain with carbol-thionin or carbol- 

 gentian- violet. Gram's stain must also of course be used. 



(b) Inoculate a mouse with a trace of the sputum. 



II. In blood, pus, etc. Microscopical examination and cultures, supple- 

 mented by the inoculation of a mouse, will render the identification of the 

 organism easy. 



HI. In pseudo-membranous sore throats. (a) Scrapings from the false 

 membrane should be stained with a single stain and by Gram's method and 

 examined 1 microscopically. 



(6) Cultures should be sown on coagulated serum as in the case of diphtheria. 

 In 15-20 hours fairly large, round, greyish, viscous colonies appear which can 

 be easily recognized with the naked eye and under the microscope. 



IV. In water. Adopt the method of cultivation in dilute carbolic acid 

 or on peptone salt agar (Chap. LXV.). After two or three passages, pour 

 gelatin plates on which the round raised dull white colonies of the pneumo- 

 bacillus will easily be recognized. Sow one of these colonies in broth, and 

 after 48 hours' incubation test the virulence of the culture on mice. 



Differential diagnosis from the pneumococcus. The pneumobacillus is 

 easily differentiated from the pneumococcus by its cultural characteristics 

 and by the fact that it is gram-negative. 



Differential diagnosis from the colon bacillus. In water examination the 

 pneumobacillus is likely to be confused with the colon bacillus, but the 

 mistake may easily be avoided by bearing in mind the following points. 



PNEUMOBACILLUS . 



COLON BACILLUS. 



Absence of motility in broth culture. 



Encapsulated. The capsule is very well marked in 

 fluids and tissues, but less visible in cultures. 



No indol formation in peptone water. 

 Ferments glycerin. 



Motile. 

 Non-encapsulated. 



Forms indol. 



Does not ferment gly- 

 cerin. 



The bacillus of rhinoscleroma. 



The bacillus of rhinoscleroma was discovered by V. Frisch. It is found in the 

 nasal and pharyngeal lesions of rhinoscleroma, and may also multiply in the deeper 

 tissues of the nasal fossae. Rona found the organism in pure culture in the enlarged 

 sub-maxillary glands in a case of the disease. 



The bacillus of rhinoscleroma is very similar to the pneumobacillus : Netter and 

 Gunther regard them as varieties of the same species. Their biological character- 

 istics however justify their being regarded as different organisms (Paltauf and 

 Bertarelli). 



Microscopical appearance. In sections of rhinoscleroma nodules, encapsulated 

 cocco-bacilli resembling the pneumobacillus in shape and size are seen in the interior 

 of certain very large cells (cells of Mickulicz) which have an excentrically placed 

 crescent-shaped nucleus. The fluid of the nodules does not appear on microscopical 

 examination to contain the organism, but by sowing cultures its presence can be 

 demonstrated. 



