On preventive inoculation / by W.M. Haffkine.

Date:
[1899?]
Catalogue details

Licence: Public Domain Mark

Credit: On preventive inoculation / by W.M. Haffkine. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    amount of disappointment, as the application of the principle in a number of instances did not give the expected results. Derivatives from Microbic Virus and their Effect. When we cultivate a pathogenic micro-organism in a liquid medium, two different elements are obtained mixed together : the bodies of the microbe and the liquid which it has modified, and into which it has secreted its own products. A modification of the entire preparation, as represented by this mixture, can be first of all obtained by filtering and separating the two elements just mentioned, and considering each of them by itself. Or else the two can be left together, and only the vitality of the microbe destroyed by some physical or chemical agent. Or the constitution and the properties of each, or of both of these elements can be, to a desired degree, altered by the admixture of chemicals, or by subjecting them to physical processes. Or, the vital and pathogenic properties of the microbe can be modi- fied by artificial breeding, and then the microbe itself, or the products of such a modified microbe, used for treatment. The immediate effect which a given virus or its derivate produces on an animal differs with the kind of virus taken, the process of modification to which it has been subjected, and the species of animals upon which it is used. The following instance may give an idea of these variations. The ordinary Indian grey, as well as the brown, monkey are sus- ceptible to the plague virus, and may contract a fatal disease from being simply pricked with an infected needle. The rabbit and guinea-pig are also susceptible to the disease. The horse, on the contrary, contracts no fatal disease after being infected even with large doses of the living virus. . If however, a plague culture be heated and the microbes killed in it, the relative susceptibilities of the monkey and the horse seem to be reversed, the guinea-pig remains comparable with the monkey, while the susceptibility of the rabbit is now like that of the horse, and not, as previously, like that of the monkey. It will require, according to several observers, a very large dose of virus so treated to produce in the monkey or in the guinea-pig any marked rise of temperature, or any alteration of the skin at the seat of injection ■ while the horse answers to the injection by almost as brisk an attack of fever as if the virus were a living one and at the seat of inoculation a tumour is produced which, if the dose be at all con- siderable, may lead to a complete mortification of the tissue. Ihe rabbit similarly answers to the injection by an attack of fever and by the formation of a hard tumour at the seat of injection. As varied as is the immediate effect of different forms of virus upon