530 BACTERIOLOGY. 
immunity against gonorrheal infection, information on 
this subject is at present wanting. Immunity in man 
seems to be similar to that produced after infection with 
the other pyogenic cocci—that is, only slight in amount 
and for a short period. It is known that a urethra or 
cervix may contain gonococci which lie dormant and 
may be innocuous in that person for years, but which 
may at any time excite an acute gonorrhea in the one 
carrying the infection or in another person. ; 
The Bacteriological Diagnosis of Gonorrhea. In view 
of the fact that several non-specific forms of urethritis 
exist, and also that micrococci morphologically similar 
to the gonococcus Neisser are often found in the normal 
urethral and vulvo-vaginal tract, it becomes a matter 
of great importance to be able to detect gonococci when 
present and to differentiate these from the non-specific 
organisms. The gonococci also which occur in old cul- 
tures and in chronic urethritis of long standing often 
take on a very diversified appearance—sometimes 
nothing but an irregular, granular mass being seen, 
which renders their detection difficult. From a medico- 
legal and social stand-point, therefore, the differential 
‘diagnosis of the gonococcus has in certain cases a very 
practical significance. 
There are two methods of differential diagnosis now 
available—the microscopical and the cultural. Animal 
inoculations are of little value, as they are not sus- 
ceptible, and, of course, human inoculations are, except 
in extremely important cases, generally impossible. In 
the microscopical diagnosis it should be borne in mind — 
that the specific gonococci in carefully made prepara- 
tions are found always largely within the pus-cells. 
Diplococci morphologically similar to gonococci occur- 
