346 BIOLOGY OF PNEUMOCOCCUS 



stance and the acetylated polysaccharide of Pneuraococcus stimu- 

 lated the development of type-specific agglutinins, precipitins, and 

 mouse-protective antibodies in the serum of normal human beings. 

 A consideration of the work of Julianelle, of Francis and Til- 

 lett, of Finland and Sutliff, and of Zozaya and Clark demonstrates 

 that the antigenic constituents of Pneumococcus introduced by the 

 intradermal route may act as immunizing agents and that, while 

 in man both type-specific immunity and corresponding type-spe- 

 cific antibodies may be developed, the skin of the rabbit possesses 

 the power so to alter pneumococcal antigen that only species-spe- 

 cific immunity results. The difference in the epidermal and possibly 

 the other somatic cells of animals of diverse species in their reac- 

 tion to the parenteral introduction of Pneumococcus and its de- 

 rivatives offers a field for study which should aid in clarifying some 

 of the questions concerning the physiological processes involved in 

 the development of the immune state. 



INHALATION AND INTRABRONCHIAL INSUFFLATION 



After giving repeated inhalations of Type I Pneumococcus, 

 Stillman 1331 ' 2 demonstrated agglutinins and protective antibodies 

 in the serum of rabbits so treated. Agglutinin production appeared 

 to remain stationary after the fifth exposure to antigen, while the 

 protective antibody content steadily rose. Repeated inhalations of 

 killed pneumococci by mice resulted in only a slight degree of im- 

 munity, but when living organisms were similarly administered a 

 definite degree of active immunity could be induced in the animals. 



Eguchi (1925) 351 confirmed Stillman's observation on the pro- 

 tection developing in mice following the inhalation of killed pneu- 

 mococci, and found further that immunity could be induced by 

 organisms of Type II as well as those of Type I. Maeji 858 also re- 

 ported that, in the case of antivirus, inhalation was an effective 

 mode of protecting young rabbits against subsequent infection 

 with Pneumococcus, and that the degree of protection increased 



