SPIRILLUM METCHNIKOVI 447 



Equal parts of defibrinated ox-blood and normal caustic potash 

 solution are mixed and sterilised in the steamer. Of this 30 c.c. are 

 mixed with 70 c.c. of 3 per cent, peptone-agar (neutral to litmus), 

 previously melted. Plates are poured and kept at 60 C. for half 

 an hour, and are then allowed to stand for twenty -four hours for 

 ammonia to evaporate. On this medium few organisms except the 

 cholera vibrio develop (but cholera-like vibrios develop equally 

 well). 



3. With other rice-like flakes several peptone-water cultures 

 should be prepared and incubated at 37 C. This is best done in 

 the small Erlenmeyer flasks containing a shallow layer (1-2 cm. 

 deep) of Dunham's peptone -water, without wool plugs, but capped 

 with a piece of sterile filter-paper. In eight to ten hours the upper 

 layers of the fluid should be examined microscopically for the 

 presence of vibrios, and gelatin, agar or Dieudonne agar plates and 

 subcultures in peptone-water are also made by inoculating from the 

 surface layer of fluid. The peptone -water culture may then be 

 tested for the presence of indole by carefully adding a few drops 

 of pure concentrated sulphuric acid. In cases of Asiatic cholera 

 the indole reaction can be obtained as early as eight hours after 

 inoculation. 



If vibrios are found in the peptone -water or other cultures, they 

 should be tested for agglutination with a high-titre cholera-immune 

 serum ; if positive results are obtained, the diagnosis is practically 

 certain. The haemolysis test should also be applied, as it is com- 

 paratively simple (p. 182). 



4. The saturation and fixation tests and Pfeiffer's reaction may 

 also be applied. 



5. If the case has lasted some time, the agglutination reaction 

 may be applied, testing the patient's serum on a known strain of 

 cholera vibrio, but this is of doubtful value. 



Spirillum Metchnikovi 



Isolated by Gamaleia from the intestinal contents of chickens 

 dead of an infectious gastro -enteritis which occurred in certain parts 

 of Russia. The disease, although resembling chicken cholera in 

 some respects, is quite distinct from the latter. This spirillum forms 

 curved rods and spiral filaments, generally slightly shorter, thicker 

 and more curved than the Koch vibrio. It is decolorised by 

 Gram's method, and is best stained with weak carbol-fuchsin. It is 

 readily cultivated, and is aerobic and facultatively anaerobic. In 



