| 摘要 |
A test strip giving a colour reaction with indole comprises a bibulous material which has been impregnated with a solution in an inert volatile solvent of 1-10% p-dimethylaminobenzaldehyde and 10-40% oxalic acid. Specified solvents are methanol and ethanol. A barrier zone may be provided to prevent capillary migration of the reagent, e.g. by applying a lacquer. The bibulous material may be filter paper, felt, porous ceramic strips or woven or matted glass fibres. The absorbency of said materials may be increased by coating with a polymer such as hydroxymethyl cellulose. The test strip may be employed to distinguish indole-producing bacteria such as Escherichia coli from Aerobacter aerogenes or Salmonella typhi. Reference has been directed by the Comptroller to Specification 779,921. |
