THE SPIRILLA 151 



a general turbidity, delicate pellicle and sulphuretted 

 hydrogen in broth cultures. 



Bacteriological Diagnosis. It is frequently possible to 

 report positively at once as to the nature of the disease 

 on the microscopical examination of one of the rice-like 

 flakes, whether from the contents of the ileum or in 

 a living patient from the stool. A minute fragment of 

 one of the flakes is suspended in sterile salt solution 

 (0-7 per cent.) and examined in a hanging drop, when 

 the spirillum of Koch is recognised by its characteristic 

 screw-like movement. If a portion of a flake be crushed 

 carefully between two cover-glasses, which are then drawn 

 apart and stained, the organisms lie with their long axes 

 in the same direction, and present the ' fish-in-stream ' 

 appearance. (Isolated vibrios may be found in normal 

 dejecta, so no significance can be attached thereto.) 



Such appearances are, however, only to be found in 

 perhaps half the cases, and it is generally necessary to 

 perform the following cultural experiments: A flake or 

 two are washed in two or three rinses of sterile salt 

 solution, and then broken up and thoroughly emulsified in 

 a little salt solution. Several gelatin tubes are melted, 

 and inoculated with loopfuls of this suspension, and 

 poured into plates, while at the same time six to twelve 

 flasks containing sterilised Dunham solution are similarly 

 inoculated. (This solution consists of peptone 1 per cent., 

 salt 1 per cent., in distilled water.) The flasks should be 

 conical Erlenmeyer ones of about 120 c.c. capacity, and 

 containing 40 to 50 c.c. of the Dunham's solution. After 

 inoculation the flasks are capped with a loose cap of 

 sterile filter-paper and incubated at 37 C. The gelatin 

 plates are examined after twenty-four hours' incubation at 

 22 C. The colonies are then macroscopic, and appear 

 microscopically as granular discs, with faintly sinuous 

 margins. After forty-eight hours there are small funnel- 

 shaped depressions in the gelatin, having yellowish points 

 at their apex, while the gelatin begins to liquefy. Frag- 

 ments of colonies having these characters are picked out 

 with a platinum needle for microscopic examination, both 

 in the hanging-drop culture and in cover-glass specimens. 

 The Dunham solution flasks are incubated for twelve hours 

 only, and are then probably cloudy from the rapid growth 

 of the organisms, and the production of indole and 



