206 THE ACUTE PNEUMONIAS 



secondary to such a local lesion as pneumonia, it is important to 

 note that in a large proportion of cases of the latter disease the 

 pneumococcus can be isolated from the blood. 



Experimental Inoculation. The pneumococcus of Fraenkel is 

 pathogenic to various animals, though the effects vary somewhat 

 with the virulence of the race used. The susceptibility of 

 different species, as Gamaleia has shown, varies to a considerable 



FIG. 71. Capsulated pneumococci in blood taken from the heart of a 

 rabbit, dead after inoculation with pneumonic sputum. 



Dried film, fixed with corrosive sublimate. Stained with carbol-fuchsin and 

 partly decolorised. x 1000. 



extent. The rabbit, and especially the mouse, are very sus- 

 ceptible ; the guinea-pig, the rat, the dog, and the sheep 

 occupy an intermediate position ; the pigeon is immune. In 

 the more susceptible animals the general type of the disease 

 produced is not pneumonia, but a general septiccemia. Thus, if 

 a rabbit or a mouse be injected subcutaneously with pneumonic 

 sputum, or with a scraping from a pneumonic lung, death 

 occurs in from twenty-four to forty-eight hours. There is some 

 fibrinous infiltration at the point of inoculation, the spleen is 



