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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    the onset of the disease, but rarely in less than a week. Corresponding to these variations and irregularities the types of fever with which sestivo-autumnal organisms are associated are various and irregular. The attempt has been made to deduce certain laws controlling these variations and apparent irregularities, and to subdivide the sestivo- autumnal organisms into certain varieties or subvarieties, but there is little agreement of opinion as to this subdivision. The following are the principal divisions of the malarial parasite which have been proposed, the essential differences in these various divisions relating, of course, to the different views held concerning the sestivo-autumnal organisms : I. Marchiafava and Celli (1889) recognized a short cycle of develop- ment of the sestivo-autumnal parasite, unaccompanied by development •of pigment, and a longer cycle with formation of a few pigment granules. Marchiafava and Bignami (1891) make two varieties of this parasite— viz. the amoeba of sestivo-autumnal quotidian, with a twenty-four-hour ■cycle, and the amoeba of sestivo-autumnal tertian, with a forty-eight- hour cycle—Amoeba febris quotidiance and Amoeba febris tertiance cestivo- ■autitmnaHs. The latter variety is the malignant tertian organism of these authors. The main differences between these varieties, according to Marchiafava and Bignami, relate to the length of the cycle of development, but there are claimed to be also minor morphological and biological differences to be mentioned subsequently (page 51). These authors, therefore, make four different varieties of the malarial parasite. They divide the malarial fevers into two main groups : 1. Mild malarial fevers which prevail in winter and spring. These are— (a) Quartan fever (with its varieties of double and triple quartan). This is caused by the Amoeba febris quartance (Golgi), which completes its life cycle in seventy-two hours. (6) Tertian fever (with double tertian and rarely certain subcontinued fevers). This is caused by the Amoeba febris tertioince (Golgi), which completes its life cycle in forty-eight hours. 2. Severe or sestivo-autumnal fevers, including the pernicious and most of the subcontinued fevers. This group comprises— («) ^Estivo-autumnal quotidian fever (to be distinguished from quo- tidians of tertian and of quartan origin), caused by the Amoeba febris quotidiance, which completes its cycle in twenty-four hours. This is the only variety of malarial parasite which can complete its life cycle in so short a period as twenty-four hours. (6) ^stivo-autumnal or malignant tertian fever, caused by the Amoeba febris tertiance cestivo-autumnalis, which completes its cycle in forty-eight hours. Most of the pernicious cases belong to this variety, the remainder to the sestivo-autumnal quotidian variety. II. Canalis (1889) does not subdivide into varieties the aestivo- autumnal parasite, which he calls the semilunar variety, but he con- siders that it has two cycles of development: («) a rapid cycle with the usual phases of amoeboid, mature, segmenting forms and spores, and (6) a slower cycle associated with the development of crescentic bodies, which he considers to be reproductive and to represent one phase in this second cycle. A similar view is held by Antolisei and Angelini.