324 ; BACTERIOLOGY. 
their vitality for from a few days to two or three 
weeks. 
Pathogenesis. The bacillus of influenza, in so far as 
experiments show, produces the disease only in monkeys 
and to a less extent in rabbits. From numerous ex- 
periments made by Pfeiffer on guinea-pigs, rats, mice, 
and pigeons these animals seem to be more or less in- 
susceptible to influenza. When a small quantity of 
culture on blood-agar, twenty-four hours old, sus- 
pended in 1 c.c. of bouillon, was injected intrave- 
nously into rabbits, Pfeiffer found that a characteristic 
pathogenic effect was produced. The first symptoms © 
were developed in one and a half to two hours after 
the injection. The animals became extremely feeble, 
lying flat upon the floor, with their limbs extended, 
and suffered from extreme dyspnea. The temperature 
rose to 41° C. or above. At the end of five or six 
hours they were able to sit up on their haunches again, 
and in twenty-four hours had recovered. Larger doses 
caused the death of the animals inoculated. These 
results are attributed by Pfeiffer to toxic products 
present in the cultures, and in none of his experiments 
was he ever able to obtain effects resembling septiceemic 
infection. In some of the experiments on monkeys, 
these animals, when cultures were rubbed into the nasal 
mucous membrane, showed a febrile condition, lasting 
for a few days, and in one case an abscess was produced 
from an injection into the subcutaneous intercellular 
tissues; but in no instance has Pfeiffer observed a mul- 
tiplication of the bacilli introduced. Recently Cantani 
has shown that it is possible to produce an infection of 
influenza in rabbits when inoculated with small doses 
(4 to 4.¢.c.) of living bacilli, provided the point of least 
