CAUSING ACUTE INFECTIONS. 
79 
The Bacillus of Influenza. 
This organism, described by Pfeifer in 1892, is a 
very small bacillus, Gram negative, aerobic, and non- 
motile. It will not grow except on media that contains 
hemoglobin and so is spoken of as hemophilic. It 
grows best in the presence of the staphylococcus. 
Heat kills the bacillus readily; an exposure of a few 
minutes at 6o° C. is sufficient. It is killed quickly by 
drying. 
Influenza or grippe is a highly infectious disease 
affecting the nose and accessory sinuses, the throat and 
lungs, and occasionally the meninges. It rarely causes 
pneumonia by itself. During the winter of 1912 the 
writer isolated influenza bacilli from the circulating 
blood of a case of septic endocarditis. The infection is 
spread by personal contact. 
To prevent the transmission of the infection the 
discharges from the nose and mouth should be col¬ 
lected and destroyed. The bacilli, however, remain in 
the secretions of the nose and mouth for long periods 
of time after recovery. They have been found also in 
healthy persons. This probably explains the sporadic 
cases. The immunity following influenza is of very 
short duration and reinfection is common. 
The epidemic of 1918, spoken of as the Spanish 
influenza, was a very virulent infection characterized 
by a high percentage of bronchopneumonic infection, 
which was extremely fatal. 
The cause of this epidemic disease while called 
