. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. 276 SPECIFIC MICRO-ORGANISMS are readily obtained on all the common media and growth occurs between 9" and 42°, best at 37° C. Broth is diffusely clouded with abundant sediment. In gelatin stab-culture, growth occurs all along the line of inoculation with funnel-shaped liquefaction (Figure 109). On agar slant the growth is con- fluent and yellowish after 24 hours. There is similar growth on Loffler's serum, often with
. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. 276 SPECIFIC MICRO-ORGANISMS are readily obtained on all the common media and growth occurs between 9" and 42°, best at 37° C. Broth is diffusely clouded with abundant sediment. In gelatin stab-culture, growth occurs all along the line of inoculation with funnel-shaped liquefaction (Figure 109). On agar slant the growth is con- fluent and yellowish after 24 hours. There is similar growth on Loffler's serum, often with liquefaction of the medium. The staphylococcus is relatively resistant to heat and chemical germicides. It is killed at 62° C. in ten minutes and at 70° C. in five minutes. V. Lingelsheiim^ found it more re- sistant, requiring ten minutes at 80° C. and an hour at 70° C. to kill his strains, but his figures cannot be accepted without further con- firmation.^ It is about as resistant to chemical poisons as any of the sporeless bacteria, and is commonly employed as a test object in the investigation of germicides. Mercuric chloride i-iooo requires three to five hours to kill staph- ylococcus cultures and much longer if the organisms are present in pus. Carbolic acid, 3 per cent, kills them in two to ten minutes. Fig. 109.âGelatine ^^^ pigment is a lipochrome and is pro- culture Ste^/jyfococcMi duced only in the presence of oxygen. The oMyeas one week old. ,. r , i-rr , r .1 11 1 â tryptic ferment diffuses out of the cells and is capable of liquefying gelatin, albumen and fibrin. The staphy- lococcus produces a soluble poison which kills leukocytes (leukocidin) and others which dissolve red blood cells (staphy- lolysin) and cause clumping of red blood cells (agglomerin). These substances are true soluble toxins and they are destroyed by heating to 80° C. Other soluble poisons seem also to be pre- sent. The bacterial cells killed by heat are only slightly toxic,
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbacteri, bookyear1920
