MORDANTS 43 



LIX. BOWHILL'S ORCEIN STAIN FOR FLAGELLA 

 AND BACTERIA. 



A saturated alcoholic solution of orcein (this solution possesses 

 greater staining powers if allowed to stand ten days before use). 



A 20 per cent, solution of tannic acid in water (dissolved by 

 heating before use. The above solutions are mixed as follows with 

 distilled water : 



Saturated alcoholic solution of orcein . 15 c. cm. 



20 per cent, watery solution of tannic acid 10 

 Distilled water .... 30 



Mix and filter. 



MORDANTS. 



For Demonstrating certain Bacteria. 

 LX. GRAM'S SOLUTION OF IODINE. 



Iodine crystals, .... 1 gramme. 



Iodide of potash, . . . 2 



Distilled water, . . . 300 c. cm. 



LXI. M. CLADIUS'S METHOD. 



One-half per cent, solution of picric acid in 



distilled water, . . . 50 c. cm. 



Distilled water, . . . . 50 



Used with a 1 per cent, watery solution of methyl violet. 



For the Demonstration of Cilia or Flagella. 

 LXIL LOFFLER'S MORDANT. 



Dissolve by heating together 



Tannin, ..... 2 grammes. 



Distilled water, . . . . 8 c. cm. 



And to this solution add 



Concentrated cold water solution of ferrous 



sulphate, . . . 5 c. cm. 



And 



Concentrated alcoholic solution of fuchsin, 1 c. cm. 



Shake well together, and after filtering, it is ready for use. 



