Frequently in slides of the blood of in fected erows there appear, after standing from twenty to thirty minutes, elongated motile forms such as were described by Danilewsky as vermieuli in his "Para sitologie Comparee du Sang"; and in order to traee their origin it is necessary to observe closely the changes in the other forms seen in the blood. Only the mature forms of the organism are seen to undergo any changes in the fresh slide of blood, the half-grown and younger forms remaining unchanged for a long time. The mature forms become rounded off, and are extruded from the corpuscle, which remains as a shadow in the plasma.
Both in the fresh and in the stained specimens of blood there can be seen dif ferences which sharply distinguish two forms of the organisms. The forms are identical in outline, but the protoplasm of one is granular and opaque as com pared with the clear hyaline protoplasm of the other. This distinction is well brought out in the stained specimen, in which the hyaline form remains almost entirely unstained, while the other takes on a well-marked blue stain with methy lene-blue. Of these it can be determined that the hyaline forms alone beeome flagellated.
These two forms, then, become ex truded alike from the corpuscle and lie free in the plasma, but generally only a very short time elaps.es before the hya line forms become flagellated, according to the process so often and so accurately described by workers on malaria. The granular forms lie qniet beside the nuclei and shadows of the red blood-corpuscles that lately contained them, but are soon seen to be approached by the flagella, which, having torn themselves away from the hyaline organism from whose protoplasm they were formed, struggle about arnong the corpuscles. These flagella, which so concentrate their pro toplasm as to form a head, swarm about the granular spheres, and one of them plunges its head into the sphere and finally wriggles its whole body into that organism. Immediately on the entrance of tbis flagellum it seems to become im possible that another should enter, for they may be watched circling about, vainly beating their heads against the organism. The flagellum which has entered continues its activity for a few moments and the pigment of the organ ism is violently churned up. Soon it be comes quiet again, and remains so for from fifteen to twenty minutes, when a conical process begins to appear at one side of the organism, the pigment col lecting mainly to the opposite side. This process grows larger and the pigment becomes more and more condensed, until finally we have a fusiform organism with a small spherical appendage crowded with pigment at one end. The other end is hyaline, and the pigment-granules which are not crowded into the small appendage are distributed superficially over the posterior part of the body. This
spindle-shaped organism moves forward with a gliding motion, sometimes turn ing at the same time on its long axis., sometimes going through arnceboid con tortions. Red corpuscles lying in its path are either punctured by the hyaline anterior end, so that the hmmoglobin is enabled to escape into the plasma, or passed over and dragged along by the adhering posterior extrenrity.
In an intense infection a great de struction of corpuscles occurs; thus in a fresh slide after standing some time even leucocytes may fall victims to the de structive force of these organisms, which have been seen to dash through them, scattering the granules into the plasma. As to the ultimate fate and true signifi cance of these forms nothing definite can as yet be stated. In the slide they keep in motion for a long time, but finally quiet down and disintegrate. The idea suggests itself from their great power of penetration that they may be the resistant forms that escape froin the body during life into the external world. The whole process described above seems to be a sexual process analogous to the sexual process seen in the lower animals and plants which occurs under unfavor able conditions and results in the forina tion of a resistant "spore." Recently blood of a woman suffering from an infection with the mstivo autum nal type of organism which a great number of crescents were to be seen. These, in the freshly-made slide of blood, ith very few exceptions, retained their crescentic shape or only a few minutes (this activity in the change of form varies greatly in specimens of blood frorn different patients). They soon drew themselves up, thus straightening out the curves of the crescent, while short ening themselves into the well-known ovoid form. After the lapse of from ten to twenty minutes most of them were quite round and extracorpuscular, the "bib" lying beside them as a delicate circle or "shadow of the red corpuscle." After from twenty to twenty-five minutes certain of the spherical forms became flagellated; others, ann. especially those in which the pigment formed a definite ring and was not diffused throughout the organisms, remaining quiet and did not become flagellated. The flagella broke from the flagellated forms and struggled about among the corpuscles, filially ap proaching the quiet spherical forms. One of them entered, agitating the pigment greatly, sometimes spinning the ring about; the remainder were unable to enter, but swarmed about, beating their heads against the wall of the organism. This occurred after from thirty-five to forty-five minutes. After the entrance of thc flagellum the organism again be e t r sy‘ died ; but, al t L In the IN% o op:t necs in NN hid] I raved tile fertilized t L. v. as mut 11(41 for n long time, no L analogou, t o the ermieulus s% as • .1.1.( :Muni NOV. 13, '97).