. A text-book upon the pathogenic Bacteria and Protozoa for students of medicine and physicians. Bacteriology; Pathogenic bacteria; Protozoa. 198 Cultivation of Micro-organisms surface for the growth of the organisms. The serum thus prepared should be white, but may have a reddish-gray color if many red corpuscles be present. It is always opaque and cannot be melted; once solid, it remains so. Koch devised a special apparatus for coagulating blood-serum. The bottom should be covered with wet cotton, a single layer of tubes placed upon it, the glass lid closed and covered with a layer of felt,
. A text-book upon the pathogenic Bacteria and Protozoa for students of medicine and physicians. Bacteriology; Pathogenic bacteria; Protozoa. 198 Cultivation of Micro-organisms surface for the growth of the organisms. The serum thus prepared should be white, but may have a reddish-gray color if many red corpuscles be present. It is always opaque and cannot be melted; once solid, it remains so. Koch devised a special apparatus for coagulating blood-serum. The bottom should be covered with wet cotton, a single layer of tubes placed upon it, the glass lid closed and covered with a layer of felt, and the temperature elevated until coagulation occurs. The repeated sterilizations may be conducted in this same apparatus, or may be done equally well in a steam apparatus, the cover of which is not completely closed, for if the temperature of the serum he raised too rapidly it is certain to bubble, so that the desirable smooth surface, upon which the culture is to be made, is ruined. 1. Fig. 38.—Koch's apparatus for coagulating and sterilizing blood-serum. Like other culture-media, blood-serum and its combinations may be sterilized in the autoclave and much time thus saved. The serum should, however, first be coagnlated, else bubbhng is apt to occur and ruin its surface. The autoclave temperature unfortunately makes the preparation very firm and hard, considerable fluid being pressed out of it. It is said that considerable advantage is secured from the addition of neutrose to blood-serum, which prevents its coagulating when heated. It can then be sterilized like bouillon and can subsequently be solidified, when desired, by the addition of some agar-agar. Fresh blood-serum can be kept on hand in the laboratory, in sterile bottles, by adding an excess of chloroform. In the process of coagulation and sterilization the chloroform is evaporated; the serum is unchanged by its presence. Loffler's Blood-serum Mixture, which seems rather better for the cultivation of some species th
Size: 1571px × 1591px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbacteri, bookyear1919
