PNEUMOCOCCAL VACCINES 483 



mococcal infection, the analogy between effects in the monkey and 

 man is not a strict one, Cecil's success in protecting the more 

 highly susceptible animal against invasion by Pneumococcus 

 pointed to even greater possibilities of the prophylactic use of 

 pneumococcal vaccines in man.* 



TYPES OF VACCINES EMPLOYED 



Saline suspensions of heat-killed pneumococci have been used by 

 Wright, Morgan, Colebrook and Dodgson, 1543 " 4 Cecil and his col- 

 leagues, by Lister, 816 Maynard, 872 and others ; similar suspensions 

 mixed with heat-killed bacteria of other species by Von Sholly 

 and Park; 1452 suspensions of the organisms in oil by Russell, 1197 

 Rosenow and Sturdivant, 1173 Howell, 661 McCoy, Hasseltine, Wads- 

 worth and Kirkbride ; 875 formalinized suspensions by Ferguson ; 436 

 pneumococci devitalized by tricresol, by phenol (Levy and 

 Aoki 801 ), and by hydrochloric acid by Kolmer and Rule; 747 soaped 

 cultures by Olson 1029 " 30 and by Larson; 789 cultures killed by 

 Merthiolate by Sutton, Kendall, and Rosenblum ; 1366 washings of 

 agar cultures — the so-called "Immunogen" — by Ferry and 

 Fisher, 438 and by Horder and Ferry; 655 extracts of pneumococci 

 and filtrates of broth cultures by Barach ; 76 autolysates by Rose- 

 now 1171 and others ; pancreatic digestion products of pneumococci 

 by Hirschfelder; 648 neutralized alkaline extracts of pneumococci 

 by Brotzu ; 150 while Ziegler 1573 employed a hypothetical substance 

 obtained by lysis of pneumococci with sodium taurocholate and 

 named by him "Pneumocholin." In these later days, purified con- 

 stituents of the pneumococcal cell are being studied for their im- 

 munizing action on large groups of men by Felton. 



DOSAGE 



Wright et aZ., 1545 " 6 in 1914, gave subcutaneous doses of from 250 

 million to 1,000 million cocci ; amounts in excess of the latter count 



* The efficacy of vaccination in arresting a spontaneous outbreak of pneu- 

 monia among stock monkeys was reported by Wisner,i525 who injected subcu- 

 taneously three doses of a saline suspension of heat-killed cultures of the strain 

 of Pneumococcus isolated from the infected laboratory animals. 



