THE BACTLLUS OF INFLUENZA. 375 



and as scattered cells. (See Fig. 66.) 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 pieces of 

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

 break them up 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 hsemo- 

 globin 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 susceptible 

 to inoculation with this organism is the monkey. By 

 intratracheal injection Pfeiffer succeeded in causing a 

 toxic condition that proved fatal. He does not regard 

 the death of the aiaimals as due to infection, but rather 

 to intoxication. The disease, as seen in man, has not 

 been reproduced in animals. 



