Malaria / by William H. Welch and William S. Thayer.

  • Welch, William Henry, 1850-1934.
Date:
[1897]
Catalogue details

Licence: Public Domain Mark

Credit: Malaria / by William H. Welch and William S. Thayer. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    bodies as phases of degeneration, the existing evidence seems upon the whole to be more in favor of this hypothesis than of any other which has been advanced. Still, if Sacharoii''s observation as to the presence of nuclear material in the flagella be correct, the objection of Grassi and Feletti, that the flagella are incapable of reproductive development because the nucleus of the parasite does not divide and enter them, would be overthrown and the hypothesis of Mannaberg and Manson would become more probable. It is evident from the description of these bodies that the use of the word flagella to designate the motile filaments is of doubtful propriety, but it is the term commonly employed. (3) There are various bodies, often seen in the examination of mala- rial blood, which are undoubtedly degenerative forms of the parasite, and others which are probably degenerative, although opinions con- cernino' the latter are divided. The more common signs of deg-eneration of the parasite are vacuolation, pseudo-gemmation, fragmentation, deformities of shape, particularly swelling, granular condition of the protoplasm, certain alterations in the arrangement and appearance of the j)ignient, disappearance of nuclear material, defects and irregulari- ties in staining, and changes in the refraction of the organism. These various degenerative changes produce forms too numerous to describe in detail. They have often been misinterpreted and described as special forms of the parasite, some of them, particularly certain vacuolated and budding forms, as special modes of reproduction. Degenerations may occur in any form of the parasite, but they are particularly common in the extracorpuscular forms. Mannaberg de- scribes the disintegration of young intracorpuscular forms, with dis- appearance of their nuclei. Fragmentation of forms extruded from the blood-corpuscles can sometimes be watched while examining fresh blood under the microscope (Plate I. Fig. 21). As a rule, only a certain number of the mature forms actually enter into reproductive segmenta- tion, and many of the spores or segments perish. If all segmented and the offspring survived, the number of the parasites after a few paroxysms would become enormous. As a matter of fact, degenerations of full- grown parasites are often observed. An interesting form of such degen- eration, foimd most frequently in the mature forms of the tertian variety, is the appearance of swollen, pigmented, so-called hydropic bodies, often much larger than red blood-corpuscles (Plate I. Figs. 18, 40), and sometimes containing vacuoles (Plate I. Figs. 18, 19, 23, 24, 40, and 42). Pound bodies simulating spores are sometimes seen in these vacuoles, but on properly stained specimens they are devoid of the nuclear mate- rial of genuine spores. Pseudo-gemmation, or the appearance of sarcodic buds on the surface of the organisms, is doubtless a form of degenera- tion. Such buds may become separated, in the form of hyaline balls, from the parent organism (Plate I. Figs. 19, 20). These evidences of degeneration may appear also in crescents and bodies belonging to this group (Plate II. Figs. 40, 41) and in flagellate bodies. From the latter small hyaline balls with a flagellum attached may break off and move around actively. Such bodies might be mistaken for flagellated spores. There is no good e^^dence that the malarial parasite ever multiplies