40 



PKACTICAL IJACTERI()L()(iY. 





DEMONSTRATION XV. 



spirillum of Aaintin Cholera — Spirillum of Finkler and Prior— Spiril- 

 lum Metchnikovi — Indol Test — Diphtheria Membrane — 

 Intra()eritoiieal Inoculation of Animals. 



1. Examine hanging drop preparations froni the 

 peptone cultures, of each of the spirilla. 



2. Make cover glass preparations from the agar and 

 the peptone cultures, of each of the spirilla. 



Stain with anilin fuchsin for 30 seconds and mount 

 in the usual manner. 



Contrast the preparations from the different culture 

 media. 



3. Make and stain cover glass preparations from the 

 10 days old, potato cultures of the Cholera spirillum. 



Many involution forms will be found. 



4. To the peptone cultures of each of the spirilla 

 add carefully, with a pipette, 10 drops of sulphuric acid. 



A rose red coloration appears with Spirillum 

 cholerse asiaticse and Spirillum Metchnikovi, but not 

 with the Spirillum of Finkler and Prior. This is due 

 to the formation by the two former of indol and nitrites. 

 Indol only gives this reaction in the presence of 

 nitrites. If no reaction follows the addition of the acid, 

 add 1 cc. of a .01% solution of potassium nitrite, freshly 

 prepared. If the reaction does not then develop, indoL 

 is certainly absent. 



/^^^ 



