336 MENINGOCOCCUS— GONOCOCCUS—CATARRH ALLS GROUP 
of the serum, when such a result might confidently have been antici- 
pated, or have reacted favorably for a brief period and then failed 
to improve. The assumption has been that these unfavorable results 
might be attributed to infection with naturally occurring "serum-fast" 
strains of meningococci, or that certain strains of meningococci might 
acquire "serum fastness" during the course of the serum treatment. 
The spinal fluid of such cases has always contained organisms morpho- 
logically and culturally indistinguishable from typical meningococci.^ 
Dopter^ studied the organisms of the nasopharynx in such a series of 
cases of meningitis with great care and discovered several organisms 
which were culturally identical but serologically distinct from the recog- 
nized type strain of the meningococcus. Such serological varieties were 
designated Parameningococci, and three types or groups of these 
have been recognized. Several observers, notably Gordon^ have cor- 
roborated this plurality of serological strains or types, of which three 
appear to belong to the parameningococcus group, the fourth being 
the classical Weichselbaum type organism. Thus, Gordon Types I, 
III and IV correspond to the parameningococci of Flexner, and 
Gordon Type II corresponds to the normal, or Weichselbaum strain. 
(Flexner I.) 
Available information suggests that these groups or types are fairly 
distinct serological entities, each maintaining its relative serological 
individuality through successive growths upon artificial media. Fur- 
thermore, the same serological strain is found both in the spinal canal 
and the nasopharynx^ of practically all acute clinical cases of epidemic 
cerebrospinal meningitis, and carriers and clinical cases alike appear to 
be infected in a majority of instances with a single, persistent strain. 
Mixed infections by two or more of the four types do not appear to have 
been definitely established. There appears to be a distinct parallelism 
between the incidence of types found in actual cases and in the carriers. 
Types I and 11 are the most common. 
Specific sera have been prepared for each of the parameningococci 
as well as the original meningococcus. Dopter^ found that a specific 
parameningococcus serum effected a rapid improvement in a small 
series of cases which failed to respond to the type meningococcus serum. 
These were shown to be parameningococcus, and not meningococcus 
infections, by careful serological studies of the organisms isolated from 
the spinal fluid. 
Distribution of the Meningococcus-Parameningococcus Group.— The 
discovery of serological strains of the meningococcus has led to their 
1 Flexner: Jour. Exp. Med., 1913, 17, 553. 
2 Compt. rend. Soc. de biol., 1909, 67, 74; ibid., 1910, 69, 600. Dopter and Pauron: 
Ibid., 1914, 77, 231. 
' Jour. Royal Army Med. Corps, 1915, 24, 455. Gordon and Murray: Ibid., 1915, 
25, 411. 
* Tulloch: Jour. Royal Army Med. Corps, 1918, 30, 115. Flack: Ibid., 1917, 28, 
113. 
6 Semaine Med., 1912, 32, 298. 
