Hæmatozoa of Malaria. Certain micro-organisms are found in the blood of persons suffering from malaria, and have lately

been very carefully studied. They do not belong to bacteria, being of animal origin; they are protozoa.

Hemamoeba Laverani. 1880.

Synonyms. Hæmatomonas Malaria (Osler). Plasmodium Malaria (Laveran).

Life Process.-A small amoeboid unpigmented body finds entry into a blood-corpuscle, and there splits up the hæmoglobin and begins to segment, forming a number of spores or granules; the corpuscle swells and finally disappears, allowing the spores and new-formed amoeba to wander free in the blood; and these then fasten themselves on to other blood-corpuscles, where they carry on a similar process.

In the Quartan variety the whole cycle lasts about 72 hours. The amoeba during the development are slightly mobile, the pigment formed is coarse and plentiful, and the corpuscle is not greatly enlarged.

The Tertian variety requires but 48 hours for its development; it fills the corpuscle entirely and distends it; is actively motile; the pigment-granules are fine.

The fever begins as the spores ripen. When the organism segments it often arranges itself into a rosette, the rosette then breaks up into separate segments, and the segments then contract into little spherules or spores.

In the Quotidian form the organisms are smaller in the peripheral blood, but the larger ones are found massed together in blood from the spleen.

Laveran Crescent.-In the less acute forms a semilunar body, rounded ends with granular masses in the center, is found stretching through the cell or showing only a small remnant of the red corpuscle. The organism may develop flagella, but it disintegrates after a time without forming spores.

Form.-Various shapes have been described, and whether they are all of one micro-organism or several distinct organisms is not yet definitely settled. They have been found in the cell, intra-corpuscular, and outside of the cell, extra-corpuscular.

Cultivation of these organisms has not yet been attained. Staining and Examination of Blood.-Take the blood of a person subject to malarial fevers, just before a paroxysm. Having first carefully cleansed the finger, a ligature is applied, and the drop of blood drawn with a needle, brought on a well-cleansed

cover-glass, and immediately covered with a second coverglass. This is now examined with a strong objective (dry system) by day-light.

If, now, a stained preparation is wanted, the cover-glasses are slid apart, passed three times through the flame, and a concentrated solution of methylin-blue left on for a few minutes.

FIG. 88.

Extra-corpuscular.

Intra-corpuscular.

VARIOUS FORMS OF PLASMODIA.

Still better is it to allow a drop of methylin-blue solution in a little ascitic fluid to flow slowly on the cover-glass before the blood has become dry. The finer structure will then be more plainly brought out. Laveran recommends the strong objective of the dry system for examining.

A drop of a watery solution of fuchsin or methylene-blue can be placed on the glass slide and a drop of blood on the cover

glass, then the cover-glass turned over on to the slide so that the two liquids mix, and examined at once.

Another Method of Staining.-Dry cover-glass in air; fix in a mixture of equal parts of alcohol and ether for half an hour; dry with filter-paper, and place for half an hour in a weak solution of methylene-blue; transfer to a 2 per cent. alcoholic solution of eosin for half an hour. Or the specimen can be stained, after fixation, in concentrated watery methylene-blue, 60; onehalf per cent. eosin solution (75 per cent. alcohol), 20; aqua destillat., 40.-M. Allow to remain for ten minutes; wash in water, and mount in xylol balsam. Blood-cells red; plasma of parasite blue; nucleus of parasite colorless; nucleolus deep blue.

Pathogenesis.-These organisms have been found only in malarial diseases, and constantly malarial paroxysms have been produced in healthy persons by inoculation of blood containing such organisms. They disappear under the use of quinine.

Significance.-Presence of the parasite confirms the diagnosis. A negative result is not proof of the absence of fever; in fresh infection the parasite is not always found; several examinations are necessary at least three to ten hours before the paroxysms. Golgi finds certain types constant in tertian, and others again peculiar to quartan.

Some, however, hold all these various forms as nothing more than changed blood-corpuscles. The impossibility of obtaining a pure culture leaves the question still in doubt.

Grassi and Feletti claim to have produced in sparrows and man, by injection of the blood of malarial persons, malarial fever, and found the specific parasites for the different forms. The amoeboid or intra-corpuscular give rise to the typical intermittent fevers. The crescent-shaped extra-corpuscular, producing the dumb ague or irregular fever; four different amoeba were found.

Hæmamoeba præcox produces the quotidian.

Bacillus of Soft Chancre. (Ducrey-Unna.)

A diplobacillus which is specific has been described by Ducrey as obtained from the secretion and in the depth and margins of the chancroid. Unna's bacillus is narrower and unbroken in the center.

Cultivation.-Unsuccessful.

Staining. With borax, methylen-blue, decolorized with weak acetic acid.

Pathogenesis. Probably a mixed infection occurs in most chancroids, especially if buboes result. The bacillus of Ducrey is not found in unopened buboes, though often contaminating the ulcerated ones.

Bacillus Icteroides. (Sanarelli, 1897.)

FIG. 89.

Bacillus icteroides (Sanarelli).

Syn.-Bacillus X. (Sternberg). Considered the cause of yellow fever by Sanarelli, but Sternberg and Novy regard this as not determined

Origin. In the tissues and blood of yellow-fever patients.

Form.-A small bacillus with rounded ends, often arranged in pairs, sometimes in threads, with lateral flagella.