. Pathogenic microörganisms; a practical manual for students, physicians, and health officers . as a rule, is between the broad ends of the oval, with the pointedends turned outward; but variation in form and arrangement of the THE DIPLOCOCCUS OF PNEUMONIA 267 cells is characteristic of this organism, there being great differencesaccording to the source from which it is obtained. As observed in thesputum and blood it is usually in pairs of lancet-shaped elements, whichare surrounded by a capsule. (See Fig. 106.) When grown in fluidculture media longer or shorter chains are frequently formed,
. Pathogenic microörganisms; a practical manual for students, physicians, and health officers . as a rule, is between the broad ends of the oval, with the pointedends turned outward; but variation in form and arrangement of the THE DIPLOCOCCUS OF PNEUMONIA 267 cells is characteristic of this organism, there being great differencesaccording to the source from which it is obtained. As observed in thesputum and blood it is usually in pairs of lancet-shaped elements, whichare surrounded by a capsule. (See Fig. 106.) When grown in fluidculture media longer or shorter chains are frequently formed, whichcan scarcely be distinguished from chains of certain streptococci,except that, as a rule, the length of the chain is less and the pairs ofdiplococci are farther apart. In cultures the individual cells are almostspherical in shape, and except in certain varieties are rarely surroundedby a capsule. ? (See Fig. 107.) The pneumococeus is by some classedas a streptococcus. Rosenow claims that a typical pneumococeus maybe easily changed into a typical streptococcus. (See preceding chapter.). *. *- J^ ^1 ? - ^^ Fig. 106.—Diplococcus of pneumonia from blood, with surrounding capsule stainedby method of Hiss. 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 cultures unlessspecial media are employed. Flagella are not present. Staining.—^It stains readily with ordinary aniline colors; it is notdecolorized after staining by Grams method. The capsule may bedemonstrated in blood or sputum by the methods given (p. 78). Biology.—^It grows equally well with or without oxygen; its parasiticnature is exhibited by the short range of temperature at which it usuallygrows—^viz., from 25° to 42° C.—best at 37° C. In the cultivation ofthis organism neutral or sUghtly alkaline media
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