PATHOGENICITY FOR EXPERIMENTAL ANIMALS 193 



that a fatal septicemia followed inoculation by that route. No 

 greater success followed the attempts of School and Sellards, al- 

 though the latter authors likewise observed fatal systemic infec- 

 tion after intravenous injection of a Type I culture. Cecil and 

 Steffen 214 " 5 were able by injecting cultures of Types I, II, and III, 

 and of one Group IV strain into the trachea to incite pneumonia 

 in Macacus rhesus, Macacus syrichtus, and Cebus capucinus. 



Among other references to the experimental production of lobar 

 pneumonia in monkeys by the intratracheal implantation of viru- 

 lent pneumococci may be mentioned the report of Francis and Ter- 

 rell, 476 who were able to induce pneumonic disease in Cynomolgos 

 monkeys with a Type III strain. The authors reported that the 

 type of infection following small doses given in winter was similar 

 to the type resulting from large doses administered in warm 

 months. The authors also noted marked individual variations in 

 the monkeys used. According to Stuppy, Falk, and Jacobson, 1853 

 Macacus rhesus and Cebus capucinus were highly resistant to in- 

 tratracheal inoculation of virulent Type I Pneumococcus. None of 

 the thirteen animals injected developed lobar pneumonia. Three 

 monkeys died from pneumococcal infection but the lungs appeared 

 to be normal, except for an increase in the number of polymor- 

 phonuclear leucocytes in the interstitial tissue, blood vessels, and 

 bronchi. 



THE CAT 



Feline animals are unsuitable for studies on pneumococcal infec- 

 tion. Robertson, Woo, Cheer, and King 1152 are apparently the only 

 authors to have reported experiments on cats in which it was pos- 

 sible by intrapleural injection of cultures of Type I and II pneu- 

 mococci to produce lobar pneumonia. However, only one animal of 

 those inoculated developed the disease. 



THE DOG 



The first reference to the use of dogs in research on Pneumococ- 



