BACTERIA IN PNEUMONIA l6l 



has been transmitted to monkeys; other animals are not suscep- 

 tible. It has never been found outside the body. Its resistance 

 is very feeble ; in water, the bacilli die in twenty-four hours, 

 but sputa containing the germs may be ejected for days and 

 weeks. Influenza bacilli are found accompanying broncho- 

 pneumonia, tuberculosis, meningitis, and other inflammations. 

 The bacillus is found in healthy individuals, to a consider- 

 able extent in the nasal secretions, and it is probably spread in 

 the fine droplets of mucus expelled in sneezing and coughing. 



Koch-Weeks Bacillus (1883-87). Cause of epidemic 

 conjunctivitis, or "pink eye"; found in the secretion. 



Form. Very minute bacillus, resembling the influenza 

 bacillus; non-motile. (See Fig. 84, p. 173.) 



Growth. They grow best on blood-serum agar, but very 

 sparsely in minute transparent colonies; non-liquefying. 



Stains. With carbolfuchsin, and is often intracellular. 

 Does not take Gram. 



Pathogenesis. Very contagious, found in 10 per cent, to 20 

 per cent, of all cases of conjunctivitis. Not infectious for 

 lower animals, and not causing any other form of disease. 



Bacillus of Pertussis (Whooping-cough) (Bordet- 

 Gengou, 1906). It has been shown that very minute 

 bacilli resembling the influenza bacillus occur in the cilia of 

 the cells lining the trachea and bronchi of persons affected 

 with whooping-cough ; these bacilli interfere with the normal 

 movement of the cilia, and cause an irritation producing 

 symptoms peculiar to the disease. 



Morphology. Very minute bacilli with rounded ends 



(Fig- 75)- 



Cultures. On potato-blood-agar, after twenty-four hours, 

 slight growth, sticky, grayish; subcultures made on blood- 

 serum and veal-agar grow readily. 



Staining. Gram-negative, stain lightly with ordinary dyes. 



Pathogenesis. By inhalation inoculation young rabbits 

 were made to develop a spasmodic cough, and the bacillus 

 was recovered from the trachea and from bronchi in pure cul- 

 tures. In the sputum of persons affected with whooping- 

 ii 



