. Laboratory work in bacteriology. Bacteriology. FILTRATION OF BACTERIAL LIQUIDS. 469 vary somewhat in thickness, and hence the rate of flow is variable. Highly albuminous fluids cannot be filtered un- less the wall of the filter is relatively thin or unless ex- tremely high pressure is employed to force the soluble pro- teins through the pores of the filter. With insufficient pressure these remain on the filter and only an aqueous liquid will pass through. The liquid to be filtered should con- tain as little suspended matter as possible. For this reason, blood-serum should be eentrifugated or
. Laboratory work in bacteriology. Bacteriology. FILTRATION OF BACTERIAL LIQUIDS. 469 vary somewhat in thickness, and hence the rate of flow is variable. Highly albuminous fluids cannot be filtered un- less the wall of the filter is relatively thin or unless ex- tremely high pressure is employed to force the soluble pro- teins through the pores of the filter. With insufficient pressure these remain on the filter and only an aqueous liquid will pass through. The liquid to be filtered should con- tain as little suspended matter as possible. For this reason, blood-serum should be eentrifugated or allowed to settle until free from corpuscles. Bouillon cultures should first be filtered through several thicknesses of paper.' The hardened, parchment-like paper (No. 575) of Schlei- cher and Schiill is well adapted for remov- ing the mass of bacteria from a liquid. A large number of filters have been devised, but most of these are far from being satisfactory for ordinary labora- tory work. One of the best'filters is that of Martin, but it can be used only with negative pressure,—that is to say by producing a vacuum in the receiving fiask. The author has described a filter' which has been found to be very useful for labor- atory work. It can be connected with an air pump, or additional pressure may be obtained by connecting with a cylinder of compressed air. It can be used for filtering large or small quantities of Fig. 66. Apparatus for filtering bacterial liquids {F. G. N.). The apparatus shown in Fig. 66 consists essentially of a glass cylinder (g) 3 cm. in diameter and 20 cm. in length. The upper end is 1 Centralblatt fiir Bakteriologie 22, p. 337, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Novy, Frederick George, 1864- . Ann Arbor [Mich. ] G. Wahr
Size: 1478px × 1690px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublisherannarbormichgwahr
