BACILLUS OF INFLUENZA. 195 



lungs for a considerable length of time; especially is this^the 

 case with tuberculous patients, in whose sputum is very often 

 found the Bacillns influenzce. By inoculating animals in the 

 brain, the nervous phenomena of this disease have been 

 easily reproduced. One attack of influenza does not seem to 

 give immunity against another. 



Closely resembling the Bacillus influenza, but unlike it, in 

 growing without the presence of haemoglobin in artificial 

 media, is the Koch- Weeks bacillus. This bacillus is found in 

 a certain form of conjunctivitis of an acute and apparently 

 epidemic nature. These bacilli are somewhat longer and 

 thinner than B. influenza, and, unlike the latter, can be grown 

 on serum-agar. There is another bacillus found in rabbits 

 causing pleuro-pneumonia in them, described by Beck as 

 motile and growing in all media. 



Pertussis Bacillus. 



History. From a case of whooping-cough Bordet and 

 Gengou in 1900 isolated a bacillus, but it was a few years 

 later before cultures were successful. 



Morphology. The Bordet-Gengou bacillus is a small, ovoid 

 bacillus found scattered among the pus-cells early in cases of 

 whooping-cough. Sometimes they occur in pairs, end to 

 end, and on account of their shortness are sometimes taken 

 for cocci. 



Staining. This bacillus may be stained with Loeffler's blue 

 or dilute carbol-fuchsin. By Gram's method it is not stained. 

 Cultivation was successful on a special medium composed of 

 potato, glycerin, agar, and defibrinated rabbit's blood. The 

 optimum temperature for growth is 37.5 C. 



Pathogenesis. Animal inoculation has been negative. The 

 almost constant presence of these bacilli in the sputum of 

 early cases of whooping-cough is the only argument for its 

 etiological significance. 



It is readily differentiated from B. influenza, which it re- 

 sembles by its inability to grow readily on haemoglobin media. 



