The principles of treatment and their applications in practical medicine / by J. Mitchell Bruce.

  • Bruce, J. Mitchell (John Mitchell), 1846-1929.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: The principles of treatment and their applications in practical medicine / by J. Mitchell Bruce. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    36/676 (page 12)
    When pathogenetic organisms penetrate the surface of the body or a mucous membrane they are met by a provision for passively 'protecting the individual cells. A micro-organism has passed the different barriers and entered the substance of the body; but it produces no morbid effect. The body is immune. This fact is familiar; the explanation of it is still a subject of discussion. The simplest form of protection against an infectious disease is the result of a previous attack of it, or of some modification of it (variola, vaccinia). The injection of attenuated virus has been employed by Pasteur and his followers as a therapeutic measure on the same principle, to render the body refractory. All this is generally recognised; but whether the blood-plasma or the cells are the seat of the change which renders the body immune is a question of great difficulty. For our present purpose the conclusion may be accepted as legitimate: that in some at least of the instances in which persons exposed to contagion resist the successful incursion of it, they are protected Ijy a previous experience of the disease, whether in fully developed or in modified form. We might even venture farther and suggest that in some instances of successful resistance to con- tagious disease, without previous experience of it in any form, the body possesses—and perhaps has acquired by a process of natural selection—a property or constitution which renders it an unfit medium for the development of specific organisms. Indeed we might dare to assume that this constitution is present in all healthy persons as regards certain organisms, although of very different degrees; and constitutes a natural provision for resistance by virtue of which (at least in part) a considerable proportion of a population always escape epidemics. Immunity very often fails. It isweaker in the infant,exposed for the first time to contagion, protected only by its inherited constitution. It unquestionably becomes exhausted by lapse of time, as the facts of vaccination and revaccination prove. It is unaccountably defective in some individuals, who suffer, for instance, from repeated attacks of such diseases as measles and scarlet fever. Visceral disease increases susceptibility to infective disease. Unsoundness of the kidneys and circulation