THE KOCH-WEEKS BACILLUS 423 



Bacteriological Diagnosis. 1. Morphological. The diagnosis of 

 whooping-cough by a microscopical examination of bronchial dis- 

 charges is not satisfactory. Influenza bacilli are frequently present 

 in the mucus and sputum from cases of pertussis, and no method is 

 available at the present time which will distinguish with certainty 

 between the two bacilli. 



2. Cultural. The isolation of B. pertussis from bronchial mucus 

 upon potato-glycerin-blood agar and its ability to grow upon ascitic 

 media free from hemoglobin separates the Bordet-Gengou organism 

 from B. influenzse. 



3. Serological. The sera of animals highly immunized to B. per- 

 tussis agglutinate the organism in high dilution, but fail to agglu- 

 tinate B. influenzse and vice versa. The serum of patients during and 

 after recovery from whooping-cough, however, agglutinates B. per- 

 tussis irregularly, and the method has no general diagnostic impor- 

 tance. The method of complement fixation similarly has not been 

 successful as applied to the diagnosis of the disease in man, although 

 the reaction is clear-cut when applied to the sera of immunized 

 animals. 1 



The etiology of whooping-cough has not been definitely established; 

 the Bordet-Gengou bacillus, however, is found in the majority of cases 

 of pertussis. Up to the present time it has not been isolated from 

 healthy subjects. 



THE KOCH-WEEKS BACILLUS. 



Acute contagious conjunctivitis or, as it is popularly known, 

 pink-eye is generally considered to be an infection of the conjunctiva 

 by a small bacillus first described by Koch. 2 Somewhat later Weeks 3 

 described the organism anew and succeeded in growing it in artificial 

 media, probably in association with other organisms. Kartulis 4 

 isolated it in pure culture on blood serum, and Kamen 5 published a 

 more complete study of the cultural characters of the organism. 



Morphology. The Koch-Weeks bacillus is a small rod-shaped 

 organism resembling the influenza bacillus. It is of about the same 

 diameter as the influenza bacillus, 0.25 micron, but somewhat longer, 

 measuring from 1 to 2 microns in length. It occurs singly and in 



1 Wollstein, loc. cit. 



2 Wien. klin. Wchnschr., 1883, 1550; Arb. a. d. kais. Gesamte., 1887, iii, 19. 



3 Arch, of Ophthalmology, 1886, xv, No. 4. 



4 Centralbl. f. Bakt., 1899, i, 449. 

 Ibid., 1889, xxv, 401, 449. 



