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 sérum 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 aérobic. Whether it may also be a facultative 
anaérobic has not been definitely determined, but it doesnot grow 
along the line of puncture when stick cultures are made in blood se- 
rum. Its rapid and abundant multiplication in gonorrhceal infection 
of mucous membranes, and the difficulties attending its cultivation 
in artificial media, show that the gonococcus is a strict parasite, 
Lestikow and Léffler, 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 (?). 
