Bacteria

Minute organisms, apparently related more nearly to plants than to animals, but perhaps to be regarded as representing a more primitive order of life than the other kingdoms, in that they are the homologues of the nucleus or rather nucleolus of cells. They are spherical, cylindrical, IMG:content-0398.jpg:[graphic] IMG:content-0399.jpg:[graphic][subsumed][subsumed][subsumed][subsumed] Different Kinds of Bacteria (mostly after Koch): A, Micr cocci, in drinking-water; B, in splenic fever; C, in cholera (Koch); D, from surface of water; E, in splenic fever (in thread-form, and with incipient spores); F, Spirillum, from putrefaction; G, Spirochete, from the teeth; II, in relapsing fever, from blood; I, different forms of cholera microbe (Koch). curved or spiral in shape, and multiply by growing in the direction of the longer he longer axis and then breaking into two equal IMG:content-0400.jpg:[blocks in formation] by means of flagella, and all produce chemical decompositions of their food before it is absorbed or a imilated. In this way we get various fermentations, putrefactions, etc., of organic substances, that but for the presence of these germs would remain unaltered. Examples of such changes are: the souring of food (such as milk), spoiling of meat, etc. As parasites in living organisms (the decomposition products acting as poi sons), they produce diseases. (See DISEASE GERMS and GERM DISEASES.) Bacteria cause the decay of fallen trees, leaves, etc., and thus prepare the food of plants. Many bacteria are useful to man; the ripening of cream and of cheese, producing the proper flavor, is due to their presence. Even in their mi ion of destruction, acting as pestilence or plague visitations, they come only as punishments for violated hygienic law; as a result, the weaker members of society are weeded out, thus causing human progre . The genera are Micrococcus , Вас terium , Bacillus , Spirillum , Vibrio , etc. The Coccus forms and Bacilli are very numerous, nearly 500 species having been described.