434 



INFLUENZA. 



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 membrane 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 follow- 

 ing in twenty-four hours. There was, however, little evidence that 

 the bacilli had undergone multiplication, the symptoms being 

 apparently produced by their toxins. In the case of rabbits, 

 intravenous injection of living cultures produces dyspnoea, mus- 

 cular 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 multi- 

 plying to any extent in their tissues. 



Cantani in a recent work succeeded in producing infection 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, afterwards infecting the substance of 

 the cord. An acute encephalitis was thus produced, and some- 

 times a purulent condition in the lateral ventricles. The bacilli, 

 were, however, never found in the blood or in other organs. The 

 symptoms produced were great dyspnoea, cardiac weakness, and 

 also a paralytic condition which appeared first in the posterior 

 limbs, and then spread to the rest of the body. The temperature 

 was at first elevated, but before death fell below normal. Similar 

 symptoms were also produced by injection of dead cultures, 

 though in this case the dose required to be five or six times 

 larger. Cantani therefore concludes that the brain substance is 

 the most suitable nidus for their growth, but agrees with Pfeiffer 

 in believing that the chief symptoms are produced by toxins 

 resident in the bodies of the bacilli. He made control experi- 

 ments by injecting other organisms, and also by injecting inert 

 substances into the cerebral tissue. 



