. Pathogenic micro-organisms, including bacteria and Protozoa; a practical manual for students, physicians and health officers. er or shorterchains consisting of from three to six or more 6>lenients and resem-bling the strej)tococcus. The cells, as they commonly occur in pairs,are somewhat oval in shape, being usually pointed at one end—hencethe name lanceolatus or lancet-shaped. When thus united the junc-tion, as a rule, is between the broad ends of the oval, with the pointedends turned outward; but variation in form and arrangement of thecells is characteristic of this orgamsni, there bei
. Pathogenic micro-organisms, including bacteria and Protozoa; a practical manual for students, physicians and health officers. er or shorterchains consisting of from three to six or more 6>lenients and resem-bling the strej)tococcus. The cells, as they commonly occur in pairs,are somewhat oval in shape, being usually pointed at one end—hencethe name lanceolatus or lancet-shaped. When thus united the junc-tion, as a rule, is between the broad ends of the oval, with the pointedends turned outward; but variation in form and arrangement of thecells is characteristic of this orgamsni, there being great diflerences 381 382 PATHOGENIC MICRO-ORGANISMS. according to the source from which it is obtained. As observedin the sputum and blood it is usually in pairs of lancet-shaped ele-ments, which are surrounded by a capsule. (See Fig. 123.) Whengrown in fluid culture media longer or shorter chains are frequentlyformed, which can scarcely be distinguished from chains of certainstreptococci, except that, as a rule, the length of the chain is less andthe pairs of diplococci are farther apart. In cultures the individual. cells are almost spherical in shape, and except in certain varietiesare rarely surrounded by a capsule. (See Fig. 124.) The pneumo-coccus is by some classed as a streptococcus. The capsule is best seen in stained preparations from the blood andexudates of fibrinous pneumonia or from the blood of an inoculatedanimal, especially the mouse, in which it is commonly, though notalways, present. It is seldom seen in preparations from culturesunless special media are employed. Flagella are not present. Staining.—It stains readily wath ordinary aniline colors; it is notdecolorized after staining by Grams method. The capsule may bedemonstrated in blood or sputum either by Grams or Welchs (glacialacetic acid) method, or the copper sulphate method of Hiss. Biology.—It grow^s equally well with or without oxygen; its parasticnature is exhibited by the short range of te
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