70 THE BACTERIA IN ASIATIC CHOLERA. [CH. 



excellent method of obtaining the comma-bacilli in almost 

 a pure cultivation, or at any rate sufficiently pure to prepare 

 from it successfully pure cultivations either in plates or in 

 test-tubes. But if at the outset other bacteria are present in 

 great numbers, one's success in obtaining anything like a 

 satisfactory cultivation of comma-bacilli in test-tubes is 

 doubtful. (See above.) 



fe) ? n gelatine the comma-bacilli show the best-marked 

 characters. Proceed after Koch's method by inoculating a 

 test-tube containing nutritive gelatine (beef-broth or beef- 

 infusion, gelatine 10 p. c., peptone i p. c., common salt i p. 

 c.,) with the platinum wire or the pointed end of a capillary 

 glass pipette charged with a tiny particle of a mucus-flake 

 from the cholera-stool or from the contents of the ileum of 

 an acute case of cholera (or what for the purpose of class- 

 demonstration is much easier with a trace of a culture con- 

 taining comma-bacilli pure or impure) ; then liquefy the 

 gelatine and shake it gently but sufficiently so as to distribute 

 well the introduced germs, and pour it out on a sterilised 

 glass or plate, or better still, into a flat-bottomed sterilised 

 glass dish sufficiently large to allow the gelatine to spread out 

 into a thin layer ; cover this immediately with a glass plate 

 or glass dish, and let the gelatine rapidly set over ice or 

 cold water, or by placing the glass dish on stone or metal 

 in a cool place ; place the dish in a moist chamber under a 

 bell-glass as mentioned in a former page, and keep it at a 

 temperature between i8and 22 C. Within this range of 

 temperature the comma-bacilli develop sufficiently well, 

 while the gelatine remains solid. 



After two, three, or four days, according to the tempera- 



(If the number of comma-bacilli and other bacteria should be 

 great, it is best first to distribute a particle of the mucus-flake in 

 sterile salt solution or broth, and from this then to inoculate gelatine for 

 making plate-cultivations, as described on a former page.) 



