FILTRATION

n. Fi2l-tra's hu3n. Lat., filtratio. Fr., /. filtrage. Ger., F., Filtrirung, Filterung, Seihung. Durchseihung, Durchseihen. It., filtrazione. Sp., filtration. The proce of pa ing fluids through porous media (filters), to separate the insoluble suspended contents from the substances held in solution. [B.] Automatic f. A proce occurring when liquid is put into a bottle closed by a twice perforated cork, into one opening of which a siphon is inserted, the outer arm being much longer than the inner, and ending in a funnel lined with the filtering material. A straight tube open at both ends is inserted through the second opening, and its lower end placed on a level with the height of the liquid to be reached in the funnel. The siphon is filled by carefully blowing through the straight tube, after which f. proceeds without further attention. ["Am. Jour, of Pharm.," June, 1887, p. 291 (a, 21).] Elective f. Fr., /. elect if. The f. of the serum of the blood through organic membranes, due to the fact that the power of adhesion of the capillary cavities of organic membranes to adjacent substances is greater 'for material charged with saline matter than for albuminoid substances mixed with the water or salts in the serum. [L, 158 (a, 21).] F's riickstand (Ger.). The undi olved substances which remain after the proce of filtering. [A, 319 (a. 21).] Membranf (Ger.). F. through a moist animal membrane (e. g., a portion of intestine, bladder, or pericardium). Morphotic substances in solution do not usually pa through; crystalloid substances in solution pa through readily if the pre ure is somewhat augmented, while in the case of colloid substances the strength of the filtrate is diminished. [A, 319 (a, 14).] [s. 59]