566 INFECTION AND IMMUNITY. 



channels, is shown by the occurrence of influenza 

 meningitis, and, rarely, of influenza peritonitis 

 (Hill and Fisch). According to Jehle, the influ- 

 enza bacillus invades the blood very frequently in 

 some of the acute exanthemata. It was found in 

 the blood in 22 out of 48 cases of scarlet fever, in 

 15 of 23 cases of measles, and in 5 of 9 cases of 

 varicella (cited by Hektoen). Hence, these dis- 

 eases would seem to create conditions favorable for 

 invasion by this bacillus. When the bacilli reach 

 the blood they probably are killed quickly. It is 

 probable that the ordinary nervous phenomena of 

 the disease are due to intoxication rather than to 

 actual infection of the nervous structures. As to 

 whether the symptoms of so-called intestinal in- 

 fluenza are due to an invasion of the intestines 

 by the bacilli or to a specialized action of circu- 

 lating toxin seems not to have been definitely set- 

 tled. There certainly is abundant opportunity for 

 infection of the intestines in cases of bronchial 

 influenza. In the bronchitis of influenza the or- 

 ganisms are found in large numbers in the smaller 

 bronchial tubes, both free and within leucocytes, 

 hence, in searching for the bacilli clinically it 

 should be certain that the sputum examined repre- 

 sents the bronchial exudate. In influenza pneu- 

 monia, which usually is of the lobular type, the 

 bacilli, mixed with pus cells and contained in 

 them, are found in large numbers in the alveoli. 

 Pure cultures of the bacillus have been obtained 

 from cases of conjunctivitis, and they occur not 

 infrequently in middle-ear complications which 

 develop during the course of the disease. Influ- 

 enza conjunctivitis sometimes occurs in epidemic 

 form, particularly in institutions and schools. 



