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NEISSERIA 



severe cases of disease with complications ; those faUing into Groups C and D were mostly 

 from simple cases with no comphoations. He therefore established a correlation between 

 the agglutinabihty and the virulence of his strains. Torrey, who together with Buckell 

 (19226) again studied the problem of agglutination, was able to a large extent to confirm 

 his original conclusions. They used 77 strains of widely separated origin. By simple 

 agglutination they were unable to obtain any definite grouping, but on the basis of absorp- 

 tion they found that their strains could be divided into 3 groups, which they called regular, 

 intermediate, and irregular. The regular strains were most generalized as regards antigenic 

 properties ; the intermediate strains were closely related to the regular types ; the irregular 

 strains exhibited marked individual variations. The regular strains were the most complex 

 antigenically, and appeared on the whole to be more virulent for man ; the irregular strains 

 were less complex, and appeared to be less virulent. These findings are analogous to those 

 of Griffith with the meningococcus. Torrey and Buckell, however, point out that the 

 antigenic structure of the gonococci is variable, and so prone to individualistic expression 

 that grouping of the organisms into sharply defined types is not warranted. 



Tulloch (1923a, b) studied 100 strains of gonococci. By simple agglutination he 

 obtained no direct evidence of grouping, but by absorption he was able to classify them 

 as follows : 



Type 



It will be seen that he classifies 92 per cent, in one group, of which 72 strains fall into 

 one sub-group. Tulloch states that Gordon found 25 out of 30 strains by absorption of 

 agglutinins to belong to a well-defined sub-group. 



Atkin (1925) was able to classify gonococci into two serological t3rpes. Most strains 

 isolated from cases of acute urethritis could be classified in Type I, whereas strains isolated 

 from chronic infection, such as cervicitis or arthritis, generally belonged to Type II. Many 

 strains agglutinated to a greater or less extent with serum of each type. Atkin suggests 

 that in the body, during the process of a chronic infection, or in the laboratory during 

 long periods of subcultivation. Type I may gradually change into Type II. The evidence 

 for this, however, is admittedly inconclusive. Atkin' s work does seem to reconcile to some 

 extent the varying results of different workers, and to agree in particular with the findings 

 of Torrey and Buckell. 



Summarizing, we may say that the serological classification of the gonococcus 

 is beset with difficulties ; that there are probably two main types, of different 

 degrees of antigenic complexity ; that between these two main types there are 

 a number of intermediate types, containing one or more antigens common to both 

 main types ; and that recently isolated strains from acute forms of the disease 

 appear to belong chiefly to Type I, while old laboratory strains, or strains isolated 

 from chronic disease, tend to belong to Type II. 



Precipitins. — Torrey (1907) prepared a precipitinogen by filtering a 5-weeks' 

 broth culture through a layer of sterile talc on filter paper. With this he obtained 

 a precipitin reaction with immune gonococcal rabbit serum. Bruckner and 

 Cristeanu macerated a culture in 0-15 per cent. NaOH, which dissolved the gono- 

 cocci in a few minutes ; the solution was filtered through porcelain. They found 

 a close relation between the gonococcus and the meningococcus ; thus anti-gonococ- 

 cal horse serum contained precipitins for both organisms ; similarly with anti- 

 meningococcal goat serum. 



