Laboratory handbook of bacteriology / [Rudolf Abel].

  • Abel, Rudolf, 1868-1942.
Date:
[1912]
Catalogue details

Licence: In copyright

Credit: Laboratory handbook of bacteriology / [Rudolf Abel]. Source: Wellcome Collection.

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    typical and easily recognized (hemispherical, yellowish- white, moist) and preparations are then made from any such suspicious colonies. Further, Neisser’s stain may bo recommended (Utjg. Rdsch. 1903, No. 214). 1. Stain for about one second or longer in a mixture of 2 parts of the following solution A to 1 part B. Solution A. Methylene blue powder 1. Absolute alcohol 20. Glacial acetic acid 50. Aq. dest. 1,000. Solution B. Crystal violet (Hochst) 1. Absolute alcohol 10. Aq. dest. 300. 2. Wash in water and at once. 3. Counter-stain in Cresoidin (cresoidin 1 part dis- solved in warm water 300, and filtered) for about three seconds. 4. Wash in water. The stain may be applied to smear preparations from serum cultures of from 14-20 hours’ growth. The diphtheria bacilli show either at one pole or at both, and occasionally in the middle as well, a blue granule in the brown stained body of the bacillus, whereas in other bacilli of the diphtheria group these granules are not exhibited in the same time. The method is not absolutely trustworthy because sometimes, though not often, pseudo-diphtheria bacilli (xerosis and such- like) exhibit granules in the manner of B. d.; further B. d. itself sometimes shows granules at a later stage, and exceptionally not at all.