THE BACILLUS OF INFLUENZA. 313 



result of these observations, Pfeiffer does not believe 

 the disease to be disseminated by either the air or the 

 water, but rather by direct infection from the catarrhal 

 secretions of the patients. 



This organism has not been found outside of the 

 human body. In the influenza patient it is present in 

 the catarrhal secretions, bronchial mucous membrane, 

 and the diseased lung tissues. It may be demonstrated 

 microscopically in the mucus by cover-slip prepara- 

 tions made in the usual way and stained with diluted 

 carbol-fuchsin, referred to above. In tlie tissues it 

 may be demonstrated in sections stained in the same 

 solution. In the sputum the bacilli are found as masses 

 and as scattered cells. (See Fig. 63.) They are also 

 found within the bodies of leucocytes, especially in the 

 later stages of the disease when convalescence has set 

 in ; at this time they appear as very small, irregular, 

 evidently degenerated bacilli within white blood- 

 corpuscles. They are also present in the nasal secre- 

 tions. 



At autopsies it is advisable to cut out small pieces of 

 the diseased tissue of about the size of a pea or a bean, 

 rub them well in a small quantity of sterile water or 

 bouillon, and make the cultures from this infusion. 

 By this procedure two advantages are gained : first, 

 a dilution of the number of bacteria present ; and, 

 secondly, the tissue furnishes the amount of haemoglo- 

 bin that is necessary for the growth of the organism. 

 Under these circumstances it is, of course, not neces- 

 sary to make a further addition of blood to the culture 

 medium. 



The only animal that has been found to be suscept- 

 ible to inoculation with this organism is the monkey. 



