. Pathogenic microörganisms; a practical manual for students, physicians, and health officers . a flora is not a physiological DOMINANT INTESTINAL BACTERIAL TYPES 317 necessity. Experiments in which animals so raised did not do well,cannot be considered evidence against this view, as the conditions of theexperiment may have deleteriously influenced development. Undoubt-edly the character and balance of the flora does act as a protectionunder some circumstances, being antagonistic to the implantation of anexogenous pathogenic type. Abnormal variations, however, in balancebetween the dominant t
. Pathogenic microörganisms; a practical manual for students, physicians, and health officers . a flora is not a physiological DOMINANT INTESTINAL BACTERIAL TYPES 317 necessity. Experiments in which animals so raised did not do well,cannot be considered evidence against this view, as the conditions of theexperiment may have deleteriously influenced development. Undoubt-edly the character and balance of the flora does act as a protectionunder some circumstances, being antagonistic to the implantation of anexogenous pathogenic type. Abnormal variations, however, in balancebetween the dominant types may be the basis of intestinal symptoms(see below). In one sense part of the intestinal flora is a potentialmenace to the host. The intestinal mucosa is an obstacle to the passageof the bacteria into the tissues, lymph, and blood. A few, however,evidently escape as the fairly frequent localization in the gall-bladder,kidney and elsewhere show. Probably this occurs constantly in smallnumbers, but because of the slight virulence of the majority of suchtypes they are promptly disposed Fig. 124.—B. bifidus, representing the various forms described; the irregularly stained orvesicular forms being from old cultures. X about 1800 diameters. Dominant Intestinal Bacterial Types.—B. bifidus.—A strict anaerobeisolated by Tissier from the stools of breast-fed infants and from thesuperficial ducts of the mammary glands of mothers. It is Gram-positive or contains a Gram-positive granule, the remainder of thebacillus being Gram-negative. In stools it is a slender bacillus with oneend tapering, the other club-shaped. In cultures it has the property ofdeveloping bifid ends. It produces acid freely but no gas from lactoseor other sugars. B. Acidophilus.—A type of bacterium characterized by its acid toler-ance. B. bulgaricus (see below) is related to this type, both beingincluded in the aciduric group. It is a Gram-positive, non-spore-bearingpleomorphic-bacillus, frequently for
Size: 1583px × 1578px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookcentury1900, bookdecade1910, bookidcu31924000235212
