PYOGENIC BACTERIA. 393 



to the difficulty of cultivating this micrococcus, and the importance, 

 under certain circumstances, of not making a mistake in its diag- 

 nosis, these characters are of exceptional value. 



Biological Characters. Bumm (1885) first succeeded in culti- 

 vating the " gonococcus " upon human blood serum, obtained from 

 the placenta of a recently delivered woman. He found that the cul- 

 tures thrive best in a moist atmosphere at 30 to 34 C. The growth 

 under the most favorable conditions is slow, and frequently no devel- 

 opment occurs when pus containing numerous gonococci is placed 

 upon blood serum in an incubating oven ; or after a slight multi- 

 plication development ceases and the cocci undergo degenerative 

 changes and quickly disappear. 



Cultures upon the surface of blood serum form a very thin, often 

 scarcely visible layer, with a smooth, moist, shining surface, and 

 by reflected light a grayish-yellow color. The growth at the end of 

 twenty-four hours may extend for a distance of a millimetre along 

 the line of inoculation, but at the end of two or three days no fur- 

 ther development occurs and the cocci soon lose their vitality. This 

 micrococcus, then, is aerobic. Whether it may also be a facultative 

 anaerobic has not been definitely determined, but it does not grow 

 along the line of puncture when stick cultures are made in blood se- 

 rum. Its rapid and abundant multiplication in gonorrhoeal infection 

 of mucous membranes, and the difficulties attending its cultivation 

 in artificial media, show that the gonococcus is a strict parasite. 



Lestikow and Loffler, prior to the publication of Bumm's impor- 

 tant monograph, had reported successful results in cultivating the 

 gonococcus upon a mixture of blood serum and gelatin. Bockhart 

 has since recommended a mixture of nutrient agar (two parts), lique- 

 fied at a temperature of 50 C., with blood serum (two to three parts) 

 at 20 C. By quickly mixing with this a little pus containing the 

 gonococcus he was able to obtain colonies upon plate cultures, made 

 by pouring the liquid medium upon sterile glass plates in the usual 

 manner. 



Ghon and Schlagenhaufer in 1893 reported that they obtained 

 good results by adding phosphate of soda to blood-serum agar, made 

 according to the method of Wertheim one part of human blood 

 serum from the placenta to two or three parts of nutrient agar. Also 

 that they were successful in cultivating the gonococcus in an acid 

 medium made by adding one part of urine to two of nutrient agar 

 (two per cent). Turro (1894) has since published the results of his 

 experiments relating to the cultivation of this micrococcus in acid 

 media. According to him it grows in normal urine, either with or 

 without the addition of peptone (one per cent) ; also in acid gelatin, 

 prepared in the usual way but without neutralization (?). 



