490 BIOLOGY OF PNEUMOCOCCUS 



less than 2 per cent of Senegalese troops reported sick after the 

 injection of 3,000 million to 6,000 million cocci. 



In the study by Von Sholly and Park, 1452 63 per cent of the sub- 

 jects vaccinated with a mixed vaccine developed after the first dose 

 mild reactions consisting of redness and soreness of the arm; the 

 same number had similar reactions following the second and larger 

 dose; while the third injection elicited a comparable condition in 

 60 per cent of the subjects. Constitutional reactions as evidenced 

 by headache, malaise, vertigo, chills, and general pain occurred in 

 19 per cent of the treated subjects after the first injection, in 27 

 per cent after the second, and in 23 per cent after the third dose. 

 In a later tabulation, Park 1054 " 6 listed severe reactions as appear- 

 ing in 3 per cent of the individuals after the first injection, 2.7 per 

 cent following the second, and 4.1 per cent after the third dose. It 

 should be borne in mind that the vaccine contained, in addition to 

 pneumococci of the first three types, streptococci of the hemolytic 

 and viridans type and the so-called influenza bacillus. One cannot 

 say to what extent these organisms participated in the toxic ac- 

 tion of the vaccine. Lister and Ordman, 819 also using a mixed vac- 

 cine, stated that in their experience while mild reactions were fre- 

 quently noted severe reactions were uncommon. Barach (1931) 76 

 encountered no immediate reactions after the intravenous or intra- 

 dermal administration of suspensions or filtrates of heat-killed 

 pneumococci. A chill was later observed in one patient so treated. 

 Although other references might be quoted, there appear no re- 

 ports of reactions following the injection of pneumococcal vac- 

 cines sufficiently severe or untoward as to preclude their use. 



APPEARANCE AND DURATION OF VACCINAL IMMUNITY 



One of the noteworthy phenomena of artificially induced, active 

 immunity to Pneumococcus is the early appearance of specific an- 

 tibodies in the circulating blood following the parenteral injec- 

 tion of pneumococcal antigens. Barach (1928) 74 " 5 was able to de- 

 tect type-specific protective substances in the serum of rabbits 



