How Antitoxines Are Developed

The new treatment of diphtheria is a practical applicatiom of the latest advances of experimental bacteriology. The general faets upon which It is based are briefly these : Certain bacterial, when üeveloprng in the organista of 'an animal or man, produce am albumimoid poison called toxine, which, circulatiug in the blood causes disease. F o-r exaniple, the Klcbs-Loeiler bacillus, growing in the throat of a child, g&nerates a toxine that produces the pystematic conditioin called diphtheria. If soine of these bacteria be removed f rom the organiilsm and placed in artificial media, Buch as broth, under proper conditioms they will grow and multiply tind produce the same toxine as before. This toxine mey be separatcd from the bacteria by filteration, and if introduced into an organism by incotilation it will produce the disease as readily as if it hadi been fooned in tlie organisni. But the virulence oï the disease thus produced will vary witJi the juantity of the toxme injected. Moreover, if the first dose given is so small as to produce only slight illness, a largor quantity may be introduced a few daye later -withooit producing a correspomding effect ; and progi-essively larger doses may be administered fmm time to time, until at last the aonimal receiies with impunity, doses many times larger tflian could possibly be borne at first. In the case oí the diphtheria toxine, for example (ototaimed, as has been salid, by growing the diphtheria bacillus in meat broth), if fifteen drops of fíltrate conta.ining the toxine be injected imtO' a vein of a horse, the a.niimal will le Bevcrely poisoned. But by repeatimg the injection from time to tinne in progressing doses, at the end of tJiree oir four months the anijnial will bear a dose of two hundred times the original qua.ntity. In other worde, the animal has beeome immune to the disease. If now a -ieiai of the immune animal be opened and some blood withdrawn, the serum of that blood (the other constituents being removed) may le injected into the system of another ainiimal or human being without ill effect, and the animal or human being thus inoculated becomes immune to the discasp. in virtue of the inoculation. More than that, if the organiBm inoculated had already acquired tle disease, the inoculation, within rcasiin.ilili' limits, is curative. For example, if a child lias been exposed to diphtheria, inoculation with the serum of a horse rendercd immune to diphtliciia .ir aliove dOKpribed will pi-eiwit development of the lisease. At a later stage inoculation tends to cure the disease. Hnese are the facts as applicd in the iiew scrvnn treatment of diphlheria. - Harper's Weekly.