EXPERIMENTAL INOCULATION. 435 



sometimes along with pyogenic cocci (Pfuhl and Walter, 

 Cornil and Durante) ; Pfuhl considers that in these the 

 path of infection is usually a direct one through the roof of 

 the nasal cavity. This observer also found post mortem in a 

 rapidly fatal case with profound general symptoms, influenza 

 bacilli in various organs, both within and outside of the 

 vessels. 



Experimental Inoculation. There is no satisfactory 

 evidence that any of the lower animals suffer from influenza 

 in natural conditions, and accordingly we cannot look for 

 very definite results from experimental inoculation. Pfeiffer, 

 by injecting living cultures of the organism into the lungs 

 of monkeys, in three cases produced a condition of fever of 

 a remittent type. Somewhat similar results were obtained 

 in one animal by smearing the uninjured mucous mem- 

 brane of the nose with a pure culture. The fever appeared 

 about twenty-four hours after the injection, and lasted for 

 from three to five days. In another case in which large 

 quantities of the bacilli were injected into the trachea, 

 marked prostration and high temperature occurred, death 

 following in twenty-four hours. There was, however, little 

 evidence that the bacilli had undergone multiplication, the 

 symptoms being apparently produced by their toxines. In 

 the case of rabbits, intravenous injection of living cultures 

 produces dyspnoea, muscular weakness, and slight rise of 

 temperature, but the bacilli rapidly disappear in the body, 

 and exactly similar symptoms are produced by injection of 

 cultures killed by the vapour of chloroform. Pfeiffer, 

 therefore, came to the conclusion that the influenza bacilli 

 contain toxic substances which can produce in animals 

 some of the substances of the disease, but that animals are 

 not liable to infection, the bacilli not having power of 

 multiplying to any extent in their tissues. 



Cantani in a recent work succeeded in producing infec- 

 tion to some extent in rabbits, by injecting the bacilli 

 directly into the anterior portion of the brain. In these 

 experiments the organisms spread to the ventricles, and then 

 through the spinal cord by means of the central canal, 



