. Biology; the story of living things. â ^/////////,^,^M,//y/////yl4^. Agglutination test for typhoid. The diagram at the left shows free-swimming bacteria, at the right the bacteria have become clumped together by theagglutins produced by the body cells. the antibodies are already formed and are at work. Just as each disease is caused by a specific kind of organism producing a specific type of toxin, so the blood forms a specific type of antibody for each toxin. Another method of receiving immunity has been recently discovered independently by two investigators, Twort and d'Herelle. The l
. Biology; the story of living things. â ^/////////,^,^M,//y/////yl4^. Agglutination test for typhoid. The diagram at the left shows free-swimming bacteria, at the right the bacteria have become clumped together by theagglutins produced by the body cells. the antibodies are already formed and are at work. Just as each disease is caused by a specific kind of organism producing a specific type of toxin, so the blood forms a specific type of antibody for each toxin. Another method of receiving immunity has been recently discovered independently by two investigators, Twort and d'Herelle. The latter made a suspension of feces from a convalescent case of dysen- tery, filtered the material, and then added the filtrate to a broth culture of dysentery and found that some substance in the filtrate killed the bacteria. This substance he called bacteriophage. It is ultra- microscopic, specific, being produced by specific bacteria, and appears, under certain conditions, to produce immunity to specific diseases. Active Acquired Immunity It has long been known that immunity can be acquired through an attack of a given contagious disease. The idea underlying this type of immunity, later developed by Pasteur, is that the causal organism may be weakened, then inoculated into a person's body, and a slight attack of the disease thus induced. Active immunity is now brought about in different ways through the introduction of (1) living organisms causing the disease, (2) attenuated or weakened organisms, (3) dead organisms, or (4) extracts of products of the organism. All of these substances may be called vaccines. The underlying prin-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hunter, George W. (George William), 1873-1948; Walter, Herbert Eugene, b. 1867; Hunter, George W. (George William), 1902-. New York,
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Keywords: ., bookauthorwalterherberteugeneb1867, bookcentury1900, bookpublish
