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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![lated. This is particularly the case with the trypanosomes in the cerebro-spinal fluid of sleeping sickness patients, so much so that at first we looked upon this as a characteristic feature of the sleeping sickness trypanosome. The examination of the same trypanosome in the blood, however, soon showed that such was not the case. When the trypanosomes are very scanty in the blood, it is best to make thick smears, from which the haemoglobin is subsequently dissolved out.1 In Ross's method2 the thick blood-film is dried and stained by one of the methods mentioned above without previous fixation. The watery solutions of the stains dissolve out the haemo- globin, at the same time staining the leucocytes and the parasites. This method is specially to be recommended for mammalian blood, which often contains very few parasites. By this method, however, the blood-film is often washed away, and, moreover, the trypano- somes are very deformed and often difficult to recognise. Ruge3 has advised fixing the blood before staining by means of a 2 per cent, solution of formalin, to which is added acetic acid to the extent of 0*5 to 1 per cent. Fixing by this method does not prevent the subsequent solution of the haemoglobin. The following method has yielded good results in our hands : fixing in absolute alcohol, then dissolving out the haemoglobin with 1 per cent, acetic acid. [Bradford and Plimmer4 got the best results by fixing with osmic and acetic acid vapours (osmic acid, 2 per cent., and glacial acetic acid, equal parts), and staining with a mixture of methylene blue and erythrosin. In the case of cerebro-spinal fluid, lymphatic gland juice, and intestinal contents of flies containing trypanosomes, it is often difficult to stain the chromatin. Gray and Tulloch5 overcame this difficulty by fixing the films while still wet in osmic acid vapour, then adding fresh blood-serum, as recommended by Leishman for sections (see below). After washing off the serum, the films were stained as usual by Leishman's stain.] [Staining1 Trypanosomes in Sections.—For staining trypanosomes and other chromatin-containing parasites in sections, Leishman6 recom- mends the following method : Paraffin sections (stuck on slides or coverslips), after treating with xylol and spirit, are washed in water and carefully blotted ; fresh blood-serum is added and allowed to remain on for five minutes ; the excess is then removed by blotting and the rest allowed to dry on. The stain is mixed—2 parts 'Leishman' to 3 of distilled water—and poured on the section, which is then covered and left for one to one and a half hours. It is advisable to put on fresh stain once or twice during that time. The stain is poured off and the section washed in distilled water. With a low power, the cell nuclei should be almost black. Decolourize and differentiate, using first a 1 in 1,500 solution of acetic acid, then a 1 in 7,000 solution of caustic soda. The acid removes excess of blue, the alkali excess of eosin, and the solutions are used alternately until 1 The method, which consists in dissolving out the haemoglobin with water or water acidulated with acetic acid, in order to show up any parasites which may be in the blood, is an old one. It has been recently reintroduced by Ronald Ross. 2 Ronald Ross, Lancet, January 10, 1903, p. 86. 3 Ruge, Deutsche med. Wochctisclir., March 19, 1903, p. 205. 1 [Bradford and Plimmer, Quart. Journ. Micr. AY., v. 45, pp. 451, 452.] ' [Gray and Tulloch, Sleeping Sickness Comm. Reports, No. 6, p. 286.] 0 [Leishman,/0///7/. Hyg.y v. 4, 1904, pp. 434-436.J](https://iiif.wellcomecollection.org/image/b21172286_0036.jp2/full/800%2C/0/default.jpg)
