Researches into the etiology of dengue / by J.W. McLaughlin.

  • McLaughlin, J. W. (James Wharton)
Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: Researches into the etiology of dengue / by J.W. McLaughlin. Source: Wellcome Collection.

    7/18 (page 675)
    smaller than the red blood corpuscles, possess a very ! large nucleus, so that there is very little or no proto-1 plasm to be seen. “The large lymph elements are a further develop¬ ment of the first, and are only to be differentiated from them in this, that they possess, around the large nuclei, a distinct border of protoplasm. “The myeloid elements are large round cells, with large oblong nuclei. V The mononuclear cells are about three times the size of the red blood corpuscles, possess round or ■oval nuclei of large size, and a considerable mass of protoplasm. The mononuclear transitional forms are to be differentiated from these cells only in this, that the nuclei are no longer round or oval, but have be¬ come indented. “The polynuclear elements are somewhat smaller, but still are always larger than the red blood corpus¬ cles, and their nuclei show, as a further differentia¬ tion, a polynuclear form; these are the true white blood corpuscles. . “The granular elements, or granules, which are! present in the cells, and which become free in the ! destruction of the same, are divided with respect to their reaction to aniline dyes. “The a or eosinophile granule is coarsely spheri¬ cal, strongly refracting, and can be stained in all the acid aniline dies. It is present in the mveloid ele- * ^ ments, seldom in the normal blood, and its number is greatly increased in leucaemic processes. “The or amphophile, is formed especially in the marrow, very often in the leucocytes in the blood of rabbits and guinea-pigs, and can be stained by acid and basic aniline dyes. “The y, or basophile plasma-cell granule, can be stained, like the bacteria, by the basic aniline dyes. These granules are coarse, slightly refracting, almost completely wanting in normal human blood, increas¬ ed in leucsemic processes, and are present normally in the blood of the lower animats, especially the white rat. “The d, or basophile granule, is fine, and can be stained in basic aniline dyes, and forms a constituent part of the large mononuclear elements. “The £, or neutrophile granule, is very fine, and fills the polynuclear elements of the human blood quite thickly, is present sparsely in' the transitional forms, and very seldom in the mononuclear elements. It can be stained by the neutral dyes. Without re¬ course to staining, these granules, as a whole, and also the products of the disintegration of the red blood corpuscles, may be confounded with micrococci. “By systematic staining with aniline dyes the a, fi and € granules can be excluded. An error is then possible only with the y and 8 granules, because these are stained in the basic aniline dyes, the same as the bacteria. These last, on account of their fine grain, can, with comparative ease, be differentiated from micrococci, and have not, as yet, been con¬ founded with them. “ The plasma-cell granules, on account of their medium size, come so near to the known forms of cocci that not only the individual free granules in the blood have been considered as cocci, but even the so-called plasma-cells in the tissues have been described as colonies of cocci. They can, on purely morphological grounds, be differentiated from them in this way, viz : That they do not all have the sym¬ metrical appearance of the cocci, but present the greatest differences in the size of the granules. “If it be desired to examine the blood for bacte¬ ria, a small drop is rapidly spread out in a thin layer, dried, fixed, and then passed three times through the flame, and then stained in thp ordinary manner. In such preparations the bacteria are sufficiently stained, but not the granules.” Prolonged heating of cover-glass preparations, or sections containing these granules, is necessary to their successful staining. The method of doing this, which is recommended, is to subject the specimens, in a drying oven, to a temperature of 240° F. for an hour; they are then prepared for the staining pro¬ cess, and may be stained with their respective dyes, acid, basic or neutral, in the manner described. As micrococci and other forms of schizomycetes do not require this prolonged heating in order to their successful staining with the aniline dyes, ren¬ ders this difference in the behavior of the protoplas¬ mic granules on the one hand, and micrococci on the other, an efficient means for their differentiation. All the glass apparatus and instruments used in the following examinations of dengue blood were sterilized by the following methods: The cover-glass and microscope slides, which had never been previ¬ ously used, were first washed in warm water with soap, then in clear water, then immersed in Seiler’s cleansing fluid, prepared as follows: Bichromate potash... 2 oz. Sulphuric acid.3 fid oz. Water. 25 fid oz. When they were taken from this solution, they were again washed in clear water, and finally, heated in the flame of a spirit lamp, just before they were used. The metal instruments were washed in warm water and soap, clear water, and then in a 5 per cent, solu¬ tion of carbolic acid; they were also heated in the flame of the lamp just before they were used. The platinum wire was fused to the end of a glass rod, this wire was sterilized always before using, by heat¬ ing it to whiteness in the lamp. The arm or finger of the person from whom the blood was obtained was washed with warm water and soap, then in a 5 per cent, solution of carbolic acid. The part was then punctured with a sterilized needle, and a small portion of the blood which ap¬ peared at the point of puncture was transferred by means of the sterilized platinum wire to the sterilized cover-glass, this was covered by another glass in order to obtain a thin layer of blood upon each of them; they were then separated, dried, and finally passed three times through the flame of the lamp, in order to thoroughly coagulate the albumen, and fix the blood elements. Blood for examination was obtained from about forty typical cases of dengue, at various times and places, and during the various stages of the disease. The results which I obtained from examinations of these different specimens were entirely uniform.