926 ANTIBACTERIAL SERA 



demonstrated the existence of immunological groups. The classification which 

 is usually accepted at this time is that of Gordon, who distinguishes four groups. 

 In the United States the Rockefeller Institute (Flexner and his co-workers) recog- 

 nized at first two principal strains and one or more intermediate forms. The Second 

 International Conference on the Standardization of Sera and Serological Tests 

 (Paris, 1922) recognized two primary groups and a third group of atypical strains. 

 Wadsworth and Kirkbride/ on the basis of agglutination and absorption tests, 

 recognize three distinct groups, corresponding to Gordon's I, II, and III, and a group 

 of atypical strains including Gordon's group IV. In the authors' opinion, based on 

 experience with a small epidemic in Kansas, Gordon's group IV must be taken into 

 account in this country. 



Preparation. — The present method, which has stood the test of long usage, is to inject 

 horses intravenously with gradually increasing doses of killed cultures two to three times a 

 week, and, after two to three weeks, substituting living cultures. These cultures should be 

 handled with rapidity, i.e., an eighteen-hour growth on a solid medium should be used. The 

 growth is washed off with salt solution, rapidly centrifugated, re-emulsified, and injected. 

 Not more than two hours should elapse between washing off the culture and the injection. 

 If this procedure is not followed, rather severe reactions are likely to result. After a period 

 of immunization of two to three months, trial bleedings are taken and the agglutination test 

 applied. Based on the results of these tests, the amount of the different strains employed can 

 be varied so as to balance the serum and eventually to produce a well-distributed polyvalent 

 serum. 



Standardization. — The testing and standardization of anti-meningococcic serum has 

 offered many difficult problems. In efforts to find a laboratory test that has relationship to 

 therapeutic value, the complement fixation test of Schwartz and McNeil, as employed by 

 the New York City Board of Health, the bacteriotropin test as employed by Miss Evans 

 of the Hygienic Laboratory and checked in the authors' laboratory, the protection tests of 

 Flexner, of Amoss and Wollstein, of Hitchens and Robinson, and of Huntoon have all 

 been eventually discarded as either being too complicated for routine use or of too difficult 

 technique, leaving, at the present time, only the agglutination test in general use. This test 

 is recognized merely as an indication that the horses have been under immunization for a 

 considerable time. 



Method of performing agglutination test. — See chapter Ixxii, by Dr. McCoy, in this 

 volume, pp. 958, 959. 



THERAPEUTICS OF ANTI-MENINGOCOCCIC SERUM 



It is usually possible to discover meningococci in the throats and nasopharynges 

 of individuals who have been in contact with cases. That these individuals are 

 actually carriers and responsible for the development of cases in others is not proved. 

 However, in the army experience of one of us (F. M. H.), isolation of meningococcus 

 carriers in an organization resulted in eliminating the disease. These meningococcus 

 carriers are extremely resistant to all known forms of local treatment, the organisms 

 persisting sometimes for many weeks. 



Practically all cases of meningitis, if investigated at an early stage, show organ- 

 isms in the blood, and cases have been known of true meningococcus septicemia which 

 did not develop meningeal symptoms. These facts have a direct bearing on treatment, 



' Wadsworth, A., and Kirkbride, M. B.: Am. J. Hyg., 6, 4, 507. July, 1926. 



