Trypanosomes and trypanosomiases / by A. Laveran and F. Mesnil ; tr. and much enl. by David Nabarro.
- Charles Louis Alphonse Laveran
- Date:
- 1907
Licence: Public Domain Mark
Credit: Trypanosomes and trypanosomiases / by A. Laveran and F. Mesnil ; tr. and much enl. by David Nabarro. Source: Wellcome Collection.
Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.
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![The preparations keep better uncovered than if covered with balsam or cedar-wood oil, in which case they rapidly lose their stain. When the staining has been successful, the protoplasm of the parasite is pale blue ; the nucleus, flagellum, and edge of the undulating membrane are purplish ; the centrosome is deep violet— a little different from the nucleus ; the undulating membrane is unstained, or stained a very pale blue (see coloured plate). The red corpuscles are pink, the nuclei of the leucocytes dark purple. Equally good results are obtained with a mixture of azure blue II and eosin. This mixture has been strongly recommended by Giemsa,1 and Grubler supplies the blue prepared according to Giemsa's directions. We have modified the method as follows :2 Dry and fix the film in absolute alcohol, then stain for ten minutes in— Watery eosin (i per 1,000) ... ... ... 2 parts. Watery solution of azure blue II (1 per 1,000) 1 part. Distilled water ... ... ... ... ... Sparts. Wash in water ; treat with 5 per cent, tannin for two to three minutes ; wash again and dry. By this method we have obtained good specimens of the trypanosomes of nagana and caderas. Finally, we have used the powders prepared by Jenner, Leish- man, J. H. Wright, etc., by mixing together solutions of eosin and methylene blue, collecting the precipitate formed, and, after washing thoroughly in distilled water, drying and pulverizing. The powder is dissolved in absolute methyl alcohol, and is then ready for use. In staining blood-films by this method, preliminary fixation of the film is unnecessary. [Leishman's stain answers admirably for trypanosomes, as well as for the malarial parasite, piroplasms, the ' Leishman body ' of kala-azar and tropical splenomegaly (see Chapter III.), and other chromatin-containing parasites. It is best used as follows : Having obtained a blood-film or a smear of an organ or tissue in the ordinary way, draw two lines with a wax pencil (preferably blue, as with the other colours the wax tends to float off) across the whole width of the slide, one on either side of the blood- smear. This prevents the stain from running all over the slide, so that 1 Giemsa, Centralbl. f. Bakter., I, Orig., v. 2>7i l9°2, P- 3°8- [Giemsa's solution is prepared as follows: Take azure II-eosin, 3 grammes, and azure II, o8 gramme ; dry and powder. Dissolve at 60° C. in 250 grammes chemically - pure glycerine, shaking the mixture to hasten solution. Add 250 grammes methyl alcohol, previously warmed to 6o° C. ; shake, leave standing for twenty-four hours at room temperature, and filter. To use, fix air-dried films in ethyl alcohol, or, more quickly (two to three minutes), in methyl alcohol ; dry with blotting-paper. Dilute the stain with water in a wide graduated vessel, shaking the mixture. Use 1 drop of stain (dropped from a drop-bottle) to about 1 c.c. distilled water, preferably warmed to 300 or 400 C. When properly mixed, pour the freshly diluted stain on to the film, and leave on for ten to fifteen minutes (or the staining may be done in the small dishes mentioned on p. 9). I hen wash in a stream of water, blot, dry, and mount in balsam. Giemsa states that it is not advisable to use his solution in the way that Leishman's stain is used. If an alkaline solution of the stain is required, add to 10 c.c. distilled water (before diluting the stain) 1 or 2 drops of a 1 per cent, solution of potassium carbonate.]](https://iiif.wellcomecollection.org/image/b21172286_0034.jp2/full/800%2C/0/default.jpg)
