68 STUDY AND IDENTIFICATION OF BACTERIA 



In addition to the genital organs, the Gonococcus may at times invade and be 

 isolated from the eye (gonorrhceal ophthalmia), the joints, rarely as a cause of 

 endocarditis and possibly as the factor in septicaemia. Grown upon hydrocele or 

 ascites agar, or blood-streaked agar, or upon blood agar from man or the rabbit, 

 the colonies appear as irregular, minute, dew-droryipots. By the second or third 

 day the involution forms are abundant, and within four to seven days the culture 

 will probably be found to be dead. Unless frequent transfers are made, it will be 

 best kept alive on blood agar. The organism grows best at 37C., and will not 

 grow below 25C. It will not grow on plain or glycerine agar or ordinary blood- 

 serum unless the transfer of considerable pus in inoculating the slants gives it a 

 suitable culture medium. In material from joints, it is in the fibrin flakes that the 

 gonococci are most apt to be found, if found at all. 



Animals do not contract gonorrhoea. Even in monkeys urethral in- 

 oculations of gonococci are negative. The organism is killed in five 

 hours by a temperature of 45C. and speedily by drying. In moist 

 smears of pus it may live for one or two days. 



By heating the blood-streaked agar tubes to s6C. for twenty minutes (inactiva- 

 tion-destroying complement and hence bactericidal power of blood on slaflt) greater 

 success in primary cultures will be obtained. 



In culturing gonococci the transfer of material to culture media 

 should be made with the least delay possible. 



The most satisfactory medium is Thalman's medium upon the slanting surface 

 of which we have deposited two or three drops of human serum. Blood may be 

 taken from a vein or the Wright U tube may be used and after centrifuging the 

 sterile serum is taken off with a capillary bulb pipette and deposited on and smeared 

 out on the slant. We now use Vedder's starch medium. 



Diplococcus Intracellularis Meningitidis (Weichselbaum, 1887). 

 This is the organism of epidemic cerebrospinal meningitis, and is fre- 

 quently termed the Meningococcus. The diplococcus is Gram-negative 

 and biscuit-shaped and is, like the Gonococcus, chiefly contained in pus 

 cells. It is also found free in the cerebrospinal fluid withdrawn from 

 cerebrospinal fever cases. There is a greater tendency to variation 

 in size and shape than is the case with the Gonococcus, which latter, in 

 fresh material, shows a striking uniformity morphologically. The 

 Meningococcus is at times not abundant. Early in the case, however, 

 the picture may be similar to that of gonorrhceal smears. 



On blood-serum the colonies appear after twenty-four to forty-eight hours as 

 discrete, very slightly hazy colonies, about Ho m ch in diameter. On serum 

 agar, as ascites or hydrocele agar, they grow best and show as faint bluish 

 colonies about i to 2 mm. in diameter. They are larger than Streptococcusjzi 

 Pneumococcus colonies. Unless^ considerable cerebrospinal fluid is transferred 



