BACILLUS OF INFLUENZA. 465 



3. The presence of the bacilli corresponded with the course of the 

 disease, and they disappeared with the cessation of the purulent 

 bronchial secretion. 



In his preliminary report of his investigations Pfeiffer says : 



" Numerous inoculation experiments were made on apes, rabbits, 

 guinea-pigs, rats, pigeons, and mice. Only in apes and rabbits 

 could positive results be obtained. The other species of animals 

 showed themselves refractory to influenza/' 



Kruse (1894) reports that he found the bacillus of Pfeiffer in 

 eighteen influenza patients examined by him in the hospital at Bonn. 

 On the other hand, he failed to find it in a considerable number of pa- 

 tients suffering from other diseases of the respiratory passages. His 

 evidence is the more valuable as he had previously (1890) reported 

 his failure to find the bacillus in typical cases of influenza. He now 

 ascribes his failure at that time to imperfect technique. 



Huber (1893), Richter (1894), Borchardt (1894), and other com- 

 petent bacteriologists, have also confirmed the results reported by 

 Pfeiffer as regards the presence of this bacillus in the bronchial 

 secretions of persons suffering from epidemic influenza, and as to 

 its biological characters. Bujwid (1893) recognizes the bacillus of 

 Pfeiffer as identical with a bacillus which he cultivated from the 

 spleen of an influenza patient in 1890. 



The researches of Weichselbaum, Kowalski, Friedrich, Kruse, 

 Bouchard, and others have given a negative result as regards the 

 presence of the influenza bacillus in the blood. They were not able 

 to demonstrate its presence either in stained preparations or by cul- 

 ture methods. Pfeiffer, also, during the last epidemic, has made 

 special researches upon this point and has never succeeded in finding 

 the bacillus. Day after day, both in mild and severe cases, he placed 

 from ten to twenty drops of blood from influenza patients on blood- 

 agar a most favorable medium but his cultures always remained 

 sterile. 



In his experiments upon rabbits, Pfeiffer (1893) found that the 

 intravenous injection of a small quantity of culture on blood-agar, 

 twenty-four hours old, suspended in one cubic centimetre of bouillon, 

 caused a characteristic pathogenic effect. The first symptoms were 

 developed within 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 dyspnoea. The tem- 

 perature mounted to 41 C. or above. At the end of five or six hours 

 thej r were able to sit upon their haunches again, and in twenty-four 

 hours had nearly recovered from all indications of ill-health. Larger 

 doses caused the death of the inoculated animals. These results are 

 due to toxic products present in the cultures, and Pfeiffer has never 

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