Elements of biology; a practical Elements of biology; a practical text-book correlating botany, zoology, and human physiology elementsofbiolog00hunt Year: [c1907] 172 BOTANY Many other diseases have been traced to bacteria. Diphtheria and asiatic cholera are tlie best known. Grippe, pneumonia, whooping cough, and colds are believed to be caused by bacteria. Other diseases, as malaria, yellow fever, and probably smallpox, scarlet fever, and measles, are due to the presence in the blood of a one-celled animal parasite. Methods of Fighting Germ Diseases. — As we have seen, dis- eases produced by
Elements of biology; a practical Elements of biology; a practical text-book correlating botany, zoology, and human physiology elementsofbiolog00hunt Year: [c1907] 172 BOTANY Many other diseases have been traced to bacteria. Diphtheria and asiatic cholera are tlie best known. Grippe, pneumonia, whooping cough, and colds are believed to be caused by bacteria. Other diseases, as malaria, yellow fever, and probably smallpox, scarlet fever, and measles, are due to the presence in the blood of a one-celled animal parasite. Methods of Fighting Germ Diseases. — As we have seen, dis- eases produced by bacteria may be caused by the bacteria being transferred from one person directly to another, or the disease may obtain a foothold in the body in food, or water, by breath- ing in the germs in the air, or by taking them into the blood through a cut or wound. In the prevention of germ diseases we must fight the germ by attacking the parasites directly with poisons that will kill them (such poisons are called germicides or disinfectants), and we must strive to make the persons coming in contact with the disease unlikely to take the disease. This insusceptibility or immunity may be either natural or acquired. Immunity may be acquired by means of such treatment as the anti-toxin treatment for diphtheria. This treatment, as the name denotes, is a method of neutralizing the poison {toxin) caused by the bacteria in the system. It was discovered a few years ago that the serum of the blood of an animal immune to diphtheria is capable of neutralizing the poison pro- duced by the diphtheria-causing bac- teria. Horses are rendered immune by giving them large doses of the diph- theria toxin or poison. The serum of the blood of these horses is then used to inoculate the patient suffering from or exposed to diphtheria, and thus the disease is checked or prevented alto- gether. A lichen {Physcia stellaris); a, spore-bearing organs. Lichens. — Lichens may be found incrust- ing rocks, tr
Size: 1288px × 1553px
Photo credit: © Bookworm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
