234 PASSIVE IMMUNIZATION 



it may be said that the efforts of all these investigators have been 

 crowned with a great degree of success. From the therapeutic 

 standpoint very little difference indeed appears to exist in the 

 efficacy of the three preparations in question, but there is still a good 

 deal of difference of opinion in regard to their mode of action. All 

 three contain agglutinins, precipitins, complement binding anti- 

 bodies, bacteriolysins, bacteriotropins and possibly also some anti- 

 toxins. From the different accounts that have been given the con- 

 clusion suggests itself that while antitoxins may possibly play a role, 

 this is unquestionably of minor importance, when compared with 

 the marked inhibitory effect which the serum exercises upon the 

 multiplication of the organisms, and to its manifest bacteriotropic 

 action, as evidenced by increased phagocytosis. 



Flexner thus records that in two children who had received sub- 

 dural injections of his serum, scarcely any extracellular diplococci 

 could be found after the first treatment, while the number of intra- 

 cellular cocci was much reduced, and that cultures could no longer 

 be secured, even though the free forms had not yet disappeared 

 altogether. 



Flexner suggests that the phagocytic digestion not only pre- 

 vents further multiplication of the diplococcus, but also that it 

 detoxicates the endotoxin by reducing it to simpler and non-toxic 

 or less toxic compounds. 



That bacteriolysins per se, however, may also play a role is 

 suggested by the observation that in a few instances in which the 

 antiserum was injected into the spinal canal of monkeys infected 

 with the diplococcus, the microorganisms disappeared without 

 marked phagocytosis, though more slowly than in the cases in which 

 outpouring of leukocytes was considerable. 



Preparation of the Antimeningococcus Serum (according to Flexner 

 and Jobling). Horses are first injected subcutaneously with cultures 

 of the diplococcus that have been heated for thirty minutes at 

 60 C., as many different strains being used collectively, as possible, 

 so as to give rise to a polyvalent serum. As first dose the equivalent 

 of a quarter surface test-tube growth on sheep-serum agar is recom- 

 mended. At each subsequent injection the dose is doubled until 

 an amount equal to four test-tube growths is given at intervals of 

 five to seven days. 



In the earlier work of Flexner and Jobling, intravenous inoculations 



