Trypanosomes and trypanosomiases / by A. Laveran and F. Mesnil ; tr. and much enl. by David Nabarro.

  • Charles Louis Alphonse Laveran
Date:
1907
Catalogue details

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 blood is spread in a thin layer on a glass slide with the edge of a visiting-card [or of another microscope slide], dried very rapidly, and fixed in absolute alcohol for five to ten minutes. The following solutions should be prepared beforehand : i. Methylene blue with silver oxide or Borrel blue. Take 50 or 60 c.c. distilled water in a flask of about 150 c.c. capacity, and add some crystals of silver nitrate. When these are dissolved, fill the flask with a concentrated solution of caustic soda and shake. A precipitate of silver oxide is formed. This is washed several times with distilled water, so as to get rid of any silver nitrate or excess of soda. A saturated watery solution of methylene blue (' medicinal methylene blue,' Hoechst) is then poured on to the silver oxide and allowed to remain for a fortnight, the flask being shaken from time to time. 2. Watery solution of eosin, 1 per 1,000 (' water-soluble ' eosin, Hoechst). 3. Solution of tannin, 5 per cent., or, better, a solution of tannin- orange, which can be obtained ready made up. The staining mixture is prepared at the time of using, according to the following formula : Solution of eosin (1 per 1,000) ... ... 4 c.c. Borrel blue ... ... .. ... ... 1 c.c. Distilled water ... ... ... ... 6 c.c. The mixture is at once poured into a flat dish, such as a Petri dish, or, better, a square or oblong dish with sloping bottom specially made for the purpose.1 The slide on which the blood-film has been spread and fixed is placed film downwards in the staining solution (a piece of glass rod or a projection from the bottom of the dish preventing the slide from touching the bottom, where a pre- cipitate nearly always forms), and left there for five to twenty minutes. Five to ten minutes' staining is long enough for most trypanosomes, especially for the mammalian parasites ; twenty minutes' staining is necessary for certain species—e.g., T. lewisi, particularly when undergoing reproduction. After removal from the staining solution the slide is well washed in a large quantity of water [or by blowing a strong stream of water on the film with a wash-bottle], then treated with the solution of tannin for several minutes, again washed in excess of water, and finally in distilled water and dried. If a precipitate is formed, which would render microscopical examination difficult, wash the film with oil of cloves, then with xylol, and gently rub the surface of the preparation with a piece of soft linen soaked in xylol. 1 [Such dishes, made of vulcanite, each to take one slide 3Xi, have been made at the suggestion of Dr. A. C. Stevenson by Messrs. Townson and Mercer, of 89, Bishopsgate Street, E.C. We have found these dishes extremely useful, especially for the prolonged staining of parasites, such as the trypanosomes and the Treponema pallidum {Spirochœta pallida) of syphilis.]
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