MICROCOCCUS GONORRHOLE 247 



injecting rabbits with small doses of the toxin immunisa- 

 tion was produced, and the blood acquired antitoxic 

 properties. A vaccine may be prepared by sterilising 

 cultures with heat, and has proved of service in chronic 

 gonorrhoeal infections. 



Clinical Diagnosis 



The diagnosis of gonorrhoea is very important, not only in clinical 

 but also in medico-legal cases. For this purpose microscopical 

 examination and culture methods are made use of. In a chronic 

 gleet the material must be examined carefully and repeatedly. 



(1) Microscopical examination. Several thin smear specimens of 

 the pus or discharge should be prepared. If the best results are 

 desired the films should be air-dried, and then fixed by placing in a 

 mixture of equal parts of alcohol and ether for fifteen minutes. 

 After fixing, a couple of the films are stained in Loffler's blue for 

 five to ten minutes, washed in water, dried and mounted. 

 Leishman's stain also gives good results, the films being merely 

 air-dried and not fixed. The preparations are then examined with 

 a T V-inch oil-immersion ; a lower power lens is useless. The ovoid 

 cocci in pairs, and occasionally in tetrads, occurring within the 

 pus-cells in groups of not less than four pairs are very characteristic. 

 Diplococci situated outside the pus-cells should be neglected (it is 

 to be noted that the nuclei of the pus-cells are deeply, the cytoplasm 

 only faintly, stained with methylene blue). The next step is to 

 ascertain the staining reaction by Gram's method. Stain two more 

 films for fifteen minutes in anilin gentian violet, dip in water, place 

 in Gram's iodine solution for two minutes, decolorise in absolute 

 alcohol until the drainings fail to stain white filter paper, and 

 counter-stain for forty-five seconds in a saturated aqueous solution 

 of Bismarck brown diluted with three times its volume of 

 distilled water. The gonococci are decolorised, and take up the 

 brown stain. In chronic urethritis the urine may be centrifuged, 

 and preparations are made from the deposit and threads and 

 stained. 



(2) Culture methods. Whenever a diagnosis is of great importance 

 an attempt should be made to cultivate the organism. Plate 

 cultures of agar smeared with blood as described (p. 245) and another 

 set with agar only should be prepared and incubated at 37 C. In 

 forty-eight hours colonies of the gonococcus should be recognisable 

 on the blood-agar, but not on the plain agar. 



