348 BIOLOGY OF PNEUMOCOCCUS 



type of tissue immunity in the lung. Heterologous cultures of liv- 

 ing pneumococci induced the local immune reaction but to a lesser 

 degree. 



ORAL, ADMINISTRATION 



When pneumococci enter the body by way of the alimentary 

 canal, their constituents may eventually reach the body cells re- 

 sponsible for the creation of immune bodies. In 1925, Eguchi 351 re- 

 ported that attempts to immunize mice by feeding them Type I 

 pneumococci met with some success when young mice were used but 

 with none in the case of adult mice. Kimura (1927), 710 neverthe- 

 less, was able to protect a large percentage of adult mice against 

 one hundred to one thousand lethal doses of Type I pneumococci 

 by dropping into the mouths of the animals large amounts of heat- 

 killed cocci of the corresponding type. A similar result attended 

 Maeji's attempts to induce active immunity in mice by spraying 

 the mouth with suspensions of pneumococci of Types I and II. 

 When the effort was successful, there developed cross-protection, 

 especially between Types I and II, with some protective action 

 against Type III strains. Maeji 849 subsequently (1929) was able 

 to immunize young mice, rats, and rabbits by the daily feeding of 

 large quantities of broth cultures of highly virulent Type III or- 

 ganisms. Although young rabbits could be rendered resistant to in- 

 fection with Type III pneumococci by the oral administration of 

 cultures of the corresponding type, no agglutinins could be de- 

 tected in the serum of the animals. 



For the purpose of increasing the permeability of the intestinal 

 mucosa for pneumococcal antigen, McDaniels (1931) 876 fed young 

 white rats first with egg-white and then thirty minutes later with 

 autolysates of Type I Pneumococcus. When tested after the lapse 

 of five days by intraperitoneal inoculation with a virulent strain 

 of Type I Pneumococcus, all the animals showed toleration of 

 many lethal doses of culture, while the rats that had received a 

 preliminary feeding with egg-white exhibited a greater resistance 



