166 IMPORTANT VARIETIES OF FISSION- FUNOI. 



tion) . The serum of animals is usually unsuitable, and upon it the 

 growth is always very slight (Bumm). 



3. We have (with Kiefer and Menge) obtained very good results 

 with a nutrient medium, always prepared when used by mixing 2% 

 agar (with 1% peptone and 5% glycerin), which has been liquefied 

 and cooled to 50°, with half its volume of ascites fluid or the fluid 

 from ovarian cysts (see Technical Appendix). 



4. We have had no good results with a nutrient medium consisting 

 of urine and glycerin-agar, or with simple glycerin-agar. 



5. Wassermann recommends the following as the best gonococcus 

 nutrient medium : 15 c.c. of swine serum, as free as possible from 

 hemoglobin, is placed in a small Erlenmeyer flask, diluted with 30 to 

 35 c.c. of water, and to this is added 2 to 3 c.c. of glycerin and, finally, 

 0.8 to 0.9 gm. (about 2% ) of nutrose (casein-sodium phosphate). The 

 whole is now mixed as thoroughly as possible by shaking and heated, 

 with constant stirring, over a free flame to the boiling-point. The 

 previously turbid fluid becomes clear upon boiling, and may be 

 properly heated in the moist oven to render it sterile. The addition 

 of the nutrose prevents the precipitate from the serum. In the prep- 

 aration of cultures an equal quantity of 2^ agar cooled to 50° is 

 poured into the flask, the two mixed and poured into a Petri dish. 

 As soon as it becomes solid, the nutrient medium is ready for use. 

 The cultures are the more luxuriant, the fresher the case of gonorrhea 

 and the less it has been treated. Growth is favored by the admission 

 of air. 



Plate Cultures. — (a) Natural size : Like the streak 

 culture. 



(b) Magnified fifty times : The great delicacy of the 

 colonies is characteristic of the gonococcus. Upon blood- 

 agar and serum-agar, as well as upon ascites glycerin- 

 agar, the colonies are transparent gray with a shade 

 of yellow, exceedingly delicate, scarcely at all, or only 

 very finely, granular. Often at the periphery the colony 

 is indistinguishable from the medium. They are very 

 slightly elevated (10, iii, below; v, ii). At this stage 

 they are very similar to the Strept. lanceolatus. In older 

 colonies the border, which was formerly smooth, becomes 

 partly wavy and irregular, the structure somewhat granu- 

 lar (10, ii), and eventually even moruloid (10, iv), yet it 

 is always more delicate than the streptococcus. If an in- 

 oculation is made upon agar smeared with blood the col- 

 onies appear prin(ij)ally at the periphery of the streak, 

 like a cloud, or, upon becoming larger, press the blood 

 aside (10, ii). The same happens if gonorrheal or blen- 

 norrhea! pus is placed upon ascites-glycerin-agar. The 



