A textbook of bacteriology : including the etiology and prevention of infective diseases and a short account of yeasts and moulds, haematozoa, and psorosperms / Edgar M. Crookshank.

  • Crookshank, Edgar M. (Edgar March), 1858-1928.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: A textbook of bacteriology : including the etiology and prevention of infective diseases and a short account of yeasts and moulds, haematozoa, and psorosperms / Edgar M. Crookshank. Source: Wellcome Collection.

    139/845 (page 98)
    In Ehrlich's method delicate sections are liable to be injured by immersion in the nitric acid, and therefore Watson-Cheyne suggested the use of formic acid. The Ziehl-Neelsen method, in which sulphuric acid is used instead of nitric acid, is much to be preferred to Ehrlich's method. Ziehl-Neelsen Method.—The solution is warmed, and sections left in it for ten minutes. The red colour, which disappears when the section is placed in weak sulphuric acid (25 per cent.), may partly return when the section is placed in water. In this case the section must be again immersed in acid and passed backwards and forwards from acid to water until the red colour has completely, or almost completely, disappeared. It must be thoroughly washed in water to remove all traces of the acid, and then placed in a watery solution of methylene blue for two or three minutes, washed again in water, immersed in alcohol, clarified in clove-oil, and mounted in the usual way. Sections are brilliantly stained, and the results are very permanent. Many special methods of staining have been introduced, and will be given in subsequent chapters with the description of the bacteria to which they apply. The methods already described are those which are more or less in constant use in studying bacteria and in conducting original researches.