PRACTICAL APPLICATIONS 369 



serum of which clumped at a dilution of i : 700,000), but this does 

 not occur in man, and the reaction is useless in diagnosis. An 

 interesting point brought out by Torrey's studies is that gonococcic 

 cultures exhibit well-marked differences inter se. The serum of the 

 rabbit alluded to above, which clumped its homologous culture at 

 i : 700,000, clumped another culture only when diluted fifty times 

 or less. This is of importance in connection with the prepara- 

 tions of vaccines and sera. Torrey also showed that antigono- 

 coccic serum contained a bacterio-precipitin. 



Clinical facts would suggest that the immunity to the gonococcus 

 is of very peculiar nature. Thus, as Ricketts well points out, 

 recovery is not due to a loss of virulence of the cocci, for they 

 remain potent to produce infection during all stages of the disease. 

 Nor is it due to the production of acquired local immunity, unless, 

 indeed, this is of such a nature that it can be very easily broken 

 down ; for the patient can be reinfected immediately after an 

 attack, or whilst the disease is in a chronic stage in some part of 

 the urethra or its diverticula. It is conceivable that the gono- 

 coccus is very easily modified by passage through other human 

 beings, and so altered that it is able to reinfect a person who has 

 just recovered from an attack caused by it in its unaltered form ; 

 but this would hardly explain the recrudescence of an apparently 

 cured discharge after excessive indulgence in alcohol. Even the 

 relationship between phagocytosis and recovery is not easy to 

 make out. Unlike other organisms, the gonococci do not appear 

 to undergo the usual morphological changes indicative of intra- 

 cellular digestion (loss of staining power and of sharp outline) 

 usually seen in bacteria after phagocytosis ; nor do the leucocytes 

 which have taken them up show degenerative changes (Ricketts). 

 And the fact that the gonococci are practically all intracellular 

 from a very early period in the disease indeed, whilst it is in 

 active progress would seem to indicate that it is a most inefficient 

 protective mechanism. Further, there is no obvious difference 

 in the phagocytosis according to the height of the opsonic 

 index, which would lead us to believe that, even when the index 

 is low, there is sufficient opsonin to enable all the available cocci 

 to be taken up. As far as it goes, the evidence leads us to think 

 that the process of cure is due to some local change possibly to 

 some exhaustion of a necessary nutrient material and not to a 

 general haemic reaction. 



Natural local immunity is very marked in the case of this 



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