THE BACILLUS OF WHOOPING COUGH 511 



3. The bacillus of sub-acute conjunctivitis. 



The organism described by Morax is a large diplo-bacillus, measuring 2 3/z long 

 and about I/A broad. It is non-motile and occurs singly or grouped in clumps or 

 chains, it stains with the basic aniline dyes and is gram-negative. In the conjunctival 

 secretions, the bacilli are free or intra- cellular. 



Morax' s bacillus is aerobic and grows only on media con taming blood or serum. 

 Cultures retain their vitality for a long time at 37 C., but are killed in 15 minutes 

 at a temperature of 58 C. 



A drop of culture placed in the conjunctival reflection in man sets up a typical 

 conjunctivitis. The bacillus has no pathogenic action on the conjunctiva of animals. 



THE BACILLUS OF WHOOPING COUGH (Bordet-Gengou). 



Numerous micro-organisms have from time to time been isolated from the 

 bronchial secretions of children suffering from whooping cough. These may be 

 regarded as belonging to one of two types : (1) bacilli which only grow on media 

 containing haemoglobin and which must be considered as identical with Pfeiffer's 

 bacillus, e.g. the organism isolated by Jochmann and Krause (p. 510) : (2) bacilli 

 which grow on ordinary media e.g. the bacilli isolated by Afanassiew, Vincenzi, 

 Czaplewski and Henger, etc. In the case of none of these organisms has proof 

 been adduced in support of their specific relationship to the disease. 



Bordet and Gengou, on the other hand, have brought forward convincing 

 arguments in favour of the specificity of an organism which they isolated 

 from the sputum of cases of whooping cough. Its appearance and charac- 

 teristics are as follows : 



1. Morphology. A small bacillus often assuming a cocco-bacillary form, 

 staining more deeply at the ends than in the centre, gram-negative, occasion- 

 ally intra-cellular and exhibiting pleomorphic features in liquid culture 

 media. 



2. Cultural characteristics. The organism grows feebly and cannot be 

 cultivated on the ordinary media either under aerobic or anaerobic conditions. 

 It grows best on an agar medium made with a 1 per cent, glycerin-potato 

 mash to which an equal volume of human or rabbit blood or serum (haemo- 

 globin is not essential) has been added. 



Primary cultures are difficult to obtain and the growth is always very 

 scanty, so scanty indeed as often to be invisible to the naked eye. By sub- 

 cultivating after incubating for 48 hours at 37 C. a better growth is obtained, 

 consisting of a narrow, whitish, slightly raised but distinctly visible streak 

 which becomes thicker and whiter in subsequent sub-cultures. Growth is 

 then easily obtained on ascitic-agar, serum-broth, blood-broth, etc. 



3. Detection and isolation of the bacillus. The bacillus of Bordet-Gengou 

 should be sought for in the early stages of the disease when the fits of coughing 

 first begin ; at a later period its isolation becomes difficult or impossible on 

 account of the numerous other organisms which have become mixed with it. 

 To isolate the organism sow a fragment of the bronchial exudate, not mixed 

 with saliva, on the surface of the special blood-potato-agar. 



4. The following facts constitute the evidence upon which the organism is claimed 

 to be the cause of the disease. 



a. The bacillus of Bordet and Gengou is agglutinated by the serum of children 

 who have recently recovered from whooping cough, though not in every case : it is 

 however always agglutinated by the serum of an immunized horse, even in a dilution 

 of 1 in 5,000. 



6. The serum of children who have recovered from the disease always contains 

 a specific immune body (sensibilisatrice] the presence of which was proved by Bordet 

 and Gengou by the method of complement fixation. 



