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 dyspncea. The tem- 
perature mounted to 41°C. or above. At the end of five or six hours 
they 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 
30 
