Serum therapy : bacterial therapeutics and vaccines / by R. T. Hewlett.

Date:
1903
Catalogue details

Licence: In copyright

Credit: Serum therapy : bacterial therapeutics and vaccines / by R. T. Hewlett. 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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    may ultimately become infected. Many varie- ties of this immunity or insusceptibility may be distinguished. In the first place, there is a natural and there is an acquired immunity; the former, natural immunity, is that which is pre- existent or inherent in the individual species ; acquired immunity, on the other hand, is that which is induced in some way. As regards natural immunity, this may be racial, appertain- ing to the race, for example: the black man is comparatively insusceptible to malaria and yellow fever, the result probably of the action of natural selection, and the Algerian sheep and white rat are immune to anthrax, while the European sheep and the brown rat are highly susceptible. Cases of individual immunity also occur ; a small proportion of persons of the white race, for instance, seem to be insusceptible to malaria. Natural immunity is doubtless due to a number of different factors, such, for example, as the body temperature, the degree of alkalinity of the blood and tissues, the presence of sub- stances, proteid in nature, which exert an in- hibitory power on the development of, or a germicidal action upon, the specific micro- organisms, phagocytosis, and the inhibitory action of other micro-organisms. As regards the latter, Metschnikoff ascribes the immunity of