MALARIAL FEVERS.
BY SAMUEL M. BEMISS, M.D.
In the medical nomenclature of this country the term malaria is synonymous with swamp or ague poison.
Malarial affections, therefore, comprise all those diseases or morbid manifestations which the swamp poison produces in the human organism.
This article is not designed to notice in a systematic manner any of these disorders which are not properly classifiable under the head of malarial fevers. It will, however, be necessary to make such references to the pathology of chronic malarial toxæmia as may serve to explain the influence this condition exerts in occasioning departures from type in the febrile attacks.
When a poison generated outside the human system obtains admission to it, and produces deleterious effects, three questions naturally arise: What is the essential character and natural history of this noxious agent? How does it obtain access to the human system? What is its mode of action when received?
In reference to the first of these questions, it must be admitted that the substantive essentiality of the malarial poison remains as yet undemonstrated. It is true, however, that the attempts at an objective study of this poison by means of the microscope and the cultivating retort point to the conclusion that it is an organism.
Its subjective or analogical study affords quite incontestable evidence in support of this conclusion. The leading features in the natural history of malaria are closely coincident with those of certain known organisms. It requires for its production suitable conditions of moisture, temperature, and a properly circumstanced breeding-place. Within certain bounds these conditions are requisite to the life and perpetuity of all organisms.
Again, when all the above-enumerated conditions correspond apparently in the most favorable degree, their continuous concurrence for a lapse of time is necessary before the poison manifests its presence. It is not improbable that this period of development may differ in different climates, but in this country we assume it to be about thirty days. If these facts related to some noxious organism visible to the eye, no doubt would be entertained that the presence of its germs in the places where it appeared was the indispensable condition. It would then follow that the concurrence of suitable meteorologic and telluric conditions with sufficient time for its growth and maturity were merely accessories to its perfect development. According to this theory, the coincidence of five circumstances is necessary before malaria can be fully matured—viz.: Its own specific germ; suitable soil or pabulum; suitable moisture; suitable temperature; sufficient time for its growth and development.