Identifier: annualreportof4189718newy (find matches)
Title: Annual report of the Commissioners of Fisheries, Game and Forests of the State of New York
Year: 1895 (1890s)
Authors: New York (State). Commissioners of Fisheries, Game and Forests
Subjects: Forests and forestry Fisheries Game and game-birds
Publisher: (Albany, N.Y. : The Commission)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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f the parasiteis to be found in the trout. The absence of all traces of conjugation leads me tobelieve that some important stages in the life history are passed in some hosts otherthan this fish. I may digress from my immediate subject long enough to point out acase which illustrates this point and which has only recently been made knownthrough researches of Major Ross in India, of Professors Koch, Grassi and others inGermany and Italy. The malaria-causing organism in man (Plasmodium malaria;) isa parasite belonging to the same group (Sporozoa) as the fish parasite here considered.Its life history was not completely known until within the last two years, when it wasdiscovered that a very important stage in its development is passed in the digestivetract of a mosquito. Professor Koch and other scientists in Germany found that themalaria germs which are taken with the blood into a mosquitos stomach, conjugatethere in pairs, a male germ fusing with a female. The copula which is formed by
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PLATE VII.—MASS OF SPORES ON THE OUTSIDE OF THE INTESTINE. FISHERIES, GAME AND FORESTS. 187 this union penetrates an epithelial cell of the gut where it forms spores. Thesespores migrate into the body cavity of the insect, ultimately finding their way into thesalivary glands, and are injected into the blood of a new human host when the pro-boscis of the mosquito is forced into the flesh. Here is a change of hosts which arewidely separated in the animal scale, one a warm-blooded vertebrate, the other aninferior invertebrate with body fluids of an entirely different nature. A similar change of hosts may occur in other forms of Sporozoa as well as in themalaria germ, and although I do not want, to insist upon it, it is certainly possible thatthe parasite which is causing the present epidemic is only one phase of some organismwhich is parasitic in some other form of animal life as well. What that form may beI have no means of knowing. The most probable hosts would be looked for amongthe

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