- VEGETABLE PARASITES.
Vegetable parasites form on the skin, on mucous membrane, on new surfaces, upon or within the body, and in certain of the fluids. They indicate the existence (on the surface, or in the fluid, affording them a habitation) of the presence of chemical decomposition, and also of the presence of some new material (albumi nous, saccharine, &c.), the result of diseased action. Their precise influence and patho logical power in the human subject are yet open to inquiry, but it is certain that the difficulty of killing them obstructs the cure of diseased states (porrigo favosa, for instance), in connection with which they form. They are referrible to fungi and algx, and commonly composed of cells arranged in a moniliform manner, and multiplying by gemmules. When forming on the external surface, they may be called epiphyta ; when within the frame, en tophyta.
The torula has been observed in the urine and in the gastric fluids (Busk) of persons labouring under saccharine diabetes ; also in the fces, and in vomited fluids under various conditions. Three to five rounded or oval cells, upon which acet;c acid produces no appreciable effect, provided sometimes with gemmules (single or more than one), —gem mules differing from themselves simply by being smaller,—the tondo. of the human sub ject is in all respects exactly like the torula cerevisim, and signifies the presence of fer mentating matters.
Mycodermatous vegetations occur as ele ments of the crust of porrigo favosa ; they germinate underneath (and never upon) the epidermis in amorphous exudation of protein basis thrown out by the cutis. Underneath the epidermis, covering the capsule, lies the amorphous exudation-matter in a thin layer ; beneath this, jointed cylindrical tubes, matted together with similar matter ; deeper still, fragments of tubes ; and yet further, free sporules in abundance : the elongated cells, forming the tubes, occasionally contain mole cules,—these are visible when magnified 800 diameters.* Acetic acid, by lessening the opacity of the amorphous matter, renders the cells and tubes more distinct. Attempts to
propagate favus by inoculation of the sporules, the matter of the crust, and the fluid of the pustules, have failed (Grubb Bennett) ; whe ther plants, healthy persons, or persons af fected with porrigo, have been made the sub jects of experiment : failures appearing to show that the parasite is incapable of germinating unless in a special soil (the amorphous exu dation-matter), and that the production of this soil constitutes the essence of the dis ease. Even when the special constitutional state exists, artificial introduction of the spo rules will not call forth exudation-matter of the quality fit for their nourishment ; for in oculation of an affected scalp fails as com pletely as that of the skin of a healthy person. So, too, the cell of cancer must have its soil of kindred hlastema, or the inoculation of its germs will fail. (See p. 124.) In plica polonica Giinsburgt found spo rules in the substance of the hair-roots ; Dr. Miinter failed in discovering them,—they are therefore not essential. Gruby detected epi phytes in sycosis between the root of the hair and its sheath.
Speaking of entophytic development on diphtheritic exudation of the mucous mem branes and skin in a former page (p. 118), the misplacement of a word gives us the appear ance of saying that vegetable growth is less common in thrush than in the similar exuda tion in pbthisis, wbereas we meant to affirm the contrary.
Dr. Bennett contributes an example of entopytic growth found amid the sputa, and in the contents of cavities, in a case of phthi sis : we have ourselves seen jointed vegetable filaments on the walls of cavities.
In the fluid of pyrosis Mr. Goodsir* found a living structure closely allied to certain ge nera of Bacillaria:, but most closely to the genus Gonium, among the Volvocinx; look ing like a wool-pack (hence the name Sareina ventriculi), bound with cord, crossing it four times at right angles, and at equal distances ; varying in diameter from to TA-0- Of an inch, and consisting ( g . 99) of sixteen four