EXPERIMENTAL INOCULATION. 409 



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 

 three to five days. In another case in which large quanti- 

 ties 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 tempera- 

 ture, 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 symptoms 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, 

 afterwards infecting the substance of the cord. An acute 

 encephalitis was thus produced, and sometimes a purulent 

 condition in the lateral ventricles. The bacilli were, how- 

 ever, 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 



