268 PATHOGENIC BACTERIA. 



Wertheim accomplished it by diluting a drop of the pus 

 in a little liquid human blood-serum, then mixing this 

 with an equal part of melted 2 per cent, agar-agar at 40 

 C. , and pouring into Petri dishes. As soon as the media 

 became firm the dishes were stood in the incubator at 

 3J° C, and in twenty-four hours the colonies could be 

 observed. Those upon the surface showed a dark centre, 

 around which a delicate granular zone could be made 

 out. 



When one of these colonies is transferred to a tube of 

 human blood-serum or the above mixture obliquely co- 

 agulated, isolated little gray colonies occur ; later these 

 become confluent and produce a delicate smeary layer 

 upon the medium. The main growth is surrounded by 

 a thin, veil-like extension which gradually fades away 

 into the medium. A slight growth occurs upon the 

 water of condensation. 



Turro says that the gonococci may also be cultivated 

 upon acid gelatin, upon gelatin containing acid urine, 

 and also in acid urine itself, in which the gonococci grow 

 near the surface, while the pus-cocci which may be mixed 

 with them sink deeper into the medium. His work has 

 not been confirmed by other investigators. 



Heiman, 1 who made an extensive series of culture-ex- 

 periments, find that the gonococcus grows best in a mixt- 

 ure of 1 part of pleuritic fluid and 2 parts of 2 per cent, 

 agar. Wright 2 prefers a mixture of urine, blood-serum, 

 peptone, and agar-agar. 



Laitinen 3 found agar-agar mixed with one-third to 

 one-half its volume of cyst or ascites fluid, and bouillon 

 containing 1 per cent, of peptone and 0.5 per cent, of 

 sodium chlorid, mixed with one-third to one-half its 

 volume of cyst or ascites fluid, very useful. The gono- 

 coccus could be maintained alive upon these media for 

 two months. L,aitinen found that the gonococcus pro- 



1 Med. Record, Dec. 19, 1886. 



2 Amer. Jour. Med. Sciences, Feb., 1895. 



3 Centralbl. f. Bakt. u. Parasitenk., June I, 1898, vol. xii., No. 20, p. 874. 



