458 BIOLOGY OF PNEUMOCOCCUS 



some rabbits by eye sensitivity to pneumococcal protein but not to 

 streptococcal protein or to suspensions of either living organism, 

 whereas similar injections of indifferent streptococci were fol- 

 lowed, in some rabbits, by eye sensitivity to suspensions of living 

 indifferent streptococci but not to suspensions of rough pneumo- 

 cocci or to nucleoprotein of either organism. Measured in terms 

 of bacterial specificity, therefore, eye sensitivity appeared to pos- 

 sess a degree of specificity not shared by skin sensitivity. A col- 

 lateral observation of Julianelle and Morris was to the effect that 

 the serum of rabbits injected intracutaneously with pneumococci 

 or indifferent streptococci contained agglutinins for both rough 

 pneumococci and indifferent streptococci, but only those rabbits 

 which received injections of Pneumococcus acquired resistance to 

 pneumococcal infection, 



Barnes* studied cutaneous reactions to pneumococcal protein 

 and capsular polysaccharide in rabbits both actively and pas- 

 sively immunized against Pneumococcus and in horses undergoing 

 active immunizing treatment for the production of antipneumo- 

 coccic serum. In rabbits actively immunized with Type II vaccine, 

 positive skin reactions were obtained following the intradermal in- 

 jection of the homologous carbohydrate. The reaction consisted 

 of an area of swelling and erythema having an average diameter 

 of fifteen to twenty millimeters or more, and the crest of the swol- 

 len area was raised to a height of four to five millimeters. Positive 

 reactions usually appeared within two hours after the injection 

 as edematous areas which, within eighteen to twenty-four hours, 

 became indurated and then persisted for more than two weeks. 

 Similar injections into normal rabbits or rabbits immunized with 

 heterologous strains of pneumococci were never followed by this 

 type of reaction, although occasionally an early, transient ery- 

 thema and slight swelling would appear, only to disappear within 

 eighteen hours. Intradermal injections of somatic protein, in the 

 amounts used, prepared from Type III pneumococci failed to 



* Unpublished observations. 



