THE GONOCOCCUS 301 



chronic gonorrhoeal infections. A so-called " detoxicated 

 vaccine " is now made. 



Clinical Diagnosis 



The diagnosis of gonorrhoea is very important, not only in 

 clinical but also in medico -legal cases. For this purpose micro- 

 scopical 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 Loftier s blue for 

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

 man's stain also gives good results, the films being merely air- 

 dried and not fixed. The preparations are then examined with 

 a good oil-immersion lens. The ovoid cocci in pairs, and occa- 

 sionally 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. The Medical Research 

 Committee recommends Jensen's modification for this purpose. 

 Thin films are prepared and fixed by heat, avoiding over-heating. 

 After cooling, the film is stained with a 0-5 per cent, aqueous solu- 

 tion of methyl violet (6B) for one quarter to half a minute. Pour 

 off the excess of stain and wash away the remainder with iodine 

 solution (iodine 1 gram, potassium iodide 2 grams, distilled water 

 ' 100 c.c.). Do not wash with water. Treat the film with more 

 iodine solution for one half to one minute. Wash off the iodine 

 solution with absolute alcohol. Treat with fresh absolute alcohol 

 once or twice until the film is decolorised ; the slide should be 

 tilted to and fro during this part of the process. Then rinse with 

 a few drops of absolute alcohol, followed immediately by counter- 

 staining with neutral red solution for one quarter to one minute 

 Finally rinse in water and dry. The neutral-red solution con- 

 sists of neutral red 1-1 i grams, 1 per cent, glacial acetic acid 2 c.c., 



