336 BACTERIOLOar. 



upon the value of microscopic examination in these 

 cases in the following terms : 



(a) In the majority of cases microscopic examination 

 is sufficient for the detection of the presence of the 

 comma bacillus in the intestinal evacuations of cholera 

 patients. 



(6) Even in the most acute cases, running a very 

 rapid course, the comma bacillus can always be found 

 in the evacuations. 



(c) In general, the number of cholera spirilla present 

 is greater the earlier death occurs ; when death is 

 postponed, and the disease continues for a longer 

 period, their number is diminished. 



{d) Should the patient not die of cholera, but from 

 some other disease, such as typhoid fever, that may be 

 engrafted upon it, the comma bacilli may disappear 

 entirely from the intestines. 



II. "With another slimy flake prepare a set of gelatin 

 plates. Place them at a temperature of from 20° to 

 22° C, and at sixteen, twenty-two, and thirty-six hours 

 observe the appearance of the colonies. Usually at 

 about twenty-two hours the colonies of this organism 

 can easily be identified by one familiar with them. 



III. With another slimy flake start a culture in a tube 

 of peptone solution — either the solution of Dunham 

 or, as Koch proposes, a solution of double the strength 

 of that of Dunham (Witte's peptone is to be used, 

 as it gives the best and most constant results). Place 

 this at 37° to 38° C, and at the end of from six to 

 eight hours prepare cover-slips from the upper layers 

 (without shaking) and examine them microscopically. 

 If comma bacilli are present and capable of multipli- 

 cation they will be found in this locality in almost 



