THE MENINGOCOCCUS GROUP 337 
designation, first as true meningococcus strains and paranieningococci, 
and, later, when the use of group sera was instituted, to their general 
classification as of Groups I, II, III and IV. This division is, of 
course, purely arbitrary. 
Types I and II, so far as information shows, are more commonly 
met with than Types III and IV, The laboratory of the British 
Commission^ for the Study of Meningitis Problems gives the following 
distribution of types in 518 cultures: 
Type. 
I. 
II. 
III. 
IV. 
Number of cultures . 
. 195.0 
218.0 
69.0 
36.0 
Percentage . . . . 
37,7 
44.0 
11.4 
7.0 
It will be seen that Types I and II were much more common in 
this series than Types III or IV. This experience is rather general. 
It is said that Type I is rather more common in the civil population 
in France and England, while Type II is somewhat more prevalent 
in the United States. This point is not definitely established, how- 
ever. In local epidemics, one or another type may be, and usually 
is, predominant. The principal significance attached to the meningo- 
coccus types at the present time is in relation to the proper selection 
of the monovalent serum which should be administered for its curative 
value. 
Serum Therapy. INIany attempts have been made to j)repare sera 
for the treatment of epidemic cerebrospinal meningitis, and two 
preparations have stood the test of actual practice in ci^•il life, KoUe 
and Wassermann's- serum and the serum prepared by Flexner and 
Jobling. The method of immunization adopted by Flexner and 
Jobling appears from available data to be essentially that of Wasser- 
mann. It is as follows: Horses are injected subcutaneously, first 
with dead cultures of meningococci, secondly with live cultures, and 
finally with autolysates of cultures. The latter are prepared by 
suspending virulent meningococci in sterile water for two days at 
37° C. and injecting the supernatant fluid. The endotoxin is liberated 
during this process, and the resulting serum obtained from the immun- 
ized animal appears to contain some "anti-endotoxin." Sera con- 
taining this anti-endotoxin are more potent curative sera' than those 
free from it. It may be that sera rich in agglutinins, lysins and 
precipitins, however, are suitable for prophylactic purposes. The 
serum thus produced appears to combine phagocytic properties, 
increasing the destruction of the organisms by leukocytes; bacteriolytic 
properties, killing and dissolving the cocci, and possibly some anti- 
toxic properties as well. It is essential, as Flexner has pointed out, not 
only to inject the serum intravenously but also to inject the serum 
directly into the spinal canal. This latter operation is accomplished by 
lumbar puncture. The turbid spinal fluid is allowed to escape through 
1 Medical Research Committee, Report No. 50, Cerebrospinal Fever, 1920, p. 128. 
2 Deutsch. med. Wchnschr., 1906, 32, 609. 
22 
