418 HEMOGLOBINOPHILIC BACILLI 



may be obtained in blood bouillon. One c.c. of sterile defibrinated 

 pigeon or rabbit blood is added to 50 c.c. of neutral nutrient broth. 

 After incubation to demonstrate its sterility, the medium is ready 

 for inoculation. 1 Attempts to grow the bacilli on hemoglobin-free 

 media have been uniformly negative; no development occurs in 

 ordinary media. 



Bacillus influenzse is an aerobic bacillus. It has not been grown in 

 the absence of oxygen. Growth does not take place below 25 C. nor 

 above 42 to 43 C. The optimum temperature is 37 C. It is possible 

 to maintain cultures by transplanting them upon fresh hemoglobin 

 media at intervals not greater than five days. Drying is rapidly fatal 

 to influenza bacilli; dried in mucus the organisms are not viable 

 after one to three days. They may remain alive in moist mucus for 

 nearly two weeks, however. Ten minutes' exposure at 57 C. kills 

 them and ordinary chemical disinfectants, bichloride of mercury 1 to 

 1000, and 5 per cent, carbolic acid, destroy them in a few minutes. 



Products of Growth. The nature of the products of metabolism of 

 the influenza bacillus are unknown. Enzymes have not been detected 

 in cultures of the organism and soluble toxins have not been demon- 

 strated. There is evidence that the cell substance of the bacilli is 

 toxic; it is probable that this toxic substance is endotoxic in character. 



Pathogenesis. The direct evidence of the etiological relationship 

 of B. influenzse to the disease influenza rests upon a single laboratory 

 infection with a pure culture of the organism. The hands were con- 

 taminated, and within twenty-four hours a typical attack of influenza 

 developed. The organisms persisted in the sputum for two months. 2 



Animal. Influenza is essentially a disease of man. Pfeiffer 3 has 

 shown that mice, rats, guinea-pigs, swine, dogs, and cats are refrac- 

 tory to infection with the living organisms. The introduction of 

 hemoglobin broth cultures of B. influenzse through the chest wall of 

 monkeys frequently causes a transient febrile reaction, and a catarrhal 

 bronchitis which, however, is not clinically comparable to influenza 

 of man. The animals recovered rapidly. Rabbits are susceptible to 

 the endotoxin of the influenza bacillus. 4 The injection of large num- 

 bers of living or killed organisms causes dyspnea and a paralysis of the 

 leg muscles. Frequently the animals die. 



1 Delius and Kolle, Ztschr. f. Hyg., 1897, xxiv, 327. 



2 Tedesco, Centralbl. f. Bakt., Orig., 1907, xliii, 323. 



3 Ztschr. f. Hyg., 1893, xiii, 357. 



4 Pfeiffer, loc. cit.; Cantani, Ztschr. f. Hyg., 1896, xxiii, 265. 



