506 BIOLOGY OF PNEUMOCOCCUS 



Two deaths occurred in the series ; in one case, a vaccine of ho- 

 mologous type had been administered and, in the other, an het- 

 erologous preparation. Sutton and associates 1366 claimed favorable 

 results attending the use of a "natural" pneumococcal antigen. 

 The mortality among the treated cases was 22.5 per cent whereas 

 42 per cent of the untreated controls died. 



Before any final appraisal can be made of the value of pneumo- 

 coccal vaccines in the treatment of lobar pneumonia there must be 

 more evidence at hand, and the evidence must be supplied by care- 

 fully controlled clinical studies in which large series of cases of 

 which some groups are given monovalent preparations of pneumo- 

 cocci of a type homologous with that infecting the patient ; other 

 groups should receive vaccines of pneumococci of a variety of sero- 

 logical types without admixture of other bacteria ; others should 

 be given similar vaccines combined with organisms of respiratory 

 origin ; while the results in all the cases in the groups studied 

 should be compared with the fate of a group of pneumonia pa- 

 tients who receive no pneumococcal antigens. Furthermore, type- 

 determinations and blood cultures should be carried out in all 

 cases studied. Without accurate and thorough observation of all 

 the manifestations following the administration of the specific 

 agent with proper bacteriological and serological controls no 

 sound verdict can be reached. 



