THERAPEUTIC IMMUNIZATION IN MAN 473 



epidemics is subject to great variations. For this reason we can 

 draw conclusions only from a large statistical material. However, 

 we know that the average mortality of epidemic meningitis before 

 the introduction of specific therapy ranged certainly higher than 65 

 per cent., and in carefully studied epidemics usually between 70 and 

 80 per cent. The statistics of Flexner showing a mortality hardly 

 exceeding 30 per cent, in unselected cases unquestionably marks a 

 wonderful therapeutic triumph. It must be remembered in consider- 

 ing the benefits of this serum that in unselected cases there must be 

 many in whom the disease has produced marked anatomical changes 

 in the central nervous system before the serum is used. It is well 

 known, of course, that the later manifestations of this disease, which 

 often lead to death with hydrocephalus, asthenia, and malnutrition, 

 are the remote results of the anatomical injuries produced by the in- 

 flammatory reactions accompanying the earlier manifestations of the 

 acute infection. These conditions of course cannot be expected to 

 yield to serum treatment. It must be assumed, therefore, that were 

 we able to obtain statistics of cases diagnosed and treated soon after 

 the onset the figures would be even more favorable than those stated 

 above. 



The action of the serum seems very largely to be an opsonic one, 

 in that, under the influences of serum, a powerful phagocytosis of 

 the meningococci takes place. It is also possible that to a certain 

 extent bactericidal action participates, in that the injection of the 

 serum into the closed space may give rise to a sort of intraspinous 

 Pfeiffer reaction with energetic ingestion of the bacteria by leu- 

 kocytes. 



The standardization of the antimeningococcus serum has been 

 worked out particularly by Jobling. 47 After attempting to stand- 

 ardize the sera by their protective power against meningococcus in- 

 fection in animals and by complement fixation, as suggested by 

 Kolle and Wassermann, Jobling has come to the conclusion that 

 neither of these methods is sufficiently regular, and that the most 

 suitable procedure is a standardization by opsonin determination. 

 The method as worked out by him depends upon determining the 

 highest dilution of the immune serum at which opsonic action 

 against the meningococcus is still evident. He suggests as a definite 

 and suitable standard of strength opsonic activity at a dilution of 

 1-5,000 of the antiserum. 



SERUM TREATMENT IN STREPTOCOCCUS INFECTIONS 



The attempts to produce powerful immune sera against strepto- 

 cocci date back to the earliest days of immunology. That the sub- 

 ject is a particularly difficult one follows from the great confusion 



47 Jobling. J. Exp. Med., Vol. 11, 1909. 



