Abstract: A process for treating bovine pericard tissue to increase resistance to biological degradation by wet-chemical processing, The wet-chemical processing consists essentially of: (i) separating any adherent fat and basal membrane from the tissue; (ii) contacting the tissue with an aqueous, alkaline solution of sodium hydroxide, potassium hydroxide, lithium hydroxide or sodium carbonate to swell the tissue; (iii) contacting the swollen tissue with an aqueous sodium chloride solution to control the swelling; (iv) contacting the tissue with a solution of a metal-ion complexing agent with a pH in excess of 11; and (v) contacting the tissue with an aqueous buffer solution having a pH of 4.5 to 6.0. Each of steps (ii)-(v) is followed by a water rinse. The pericard tissue is then dried and sterilized.

Abstract: Apparatus for the determination of the sedimentation rate of red blood cells comprising a sedimentation tube adapted to hold a blood column, and a closure valve on one end of the sedimentation tube with said closure valve having a self-sealing valve means.

Abstract: A filter element that is particularly suitable for filtration of blood is made by compacting a mixture of fibers that is non-injurious to blood and one component of which has a lower softening temperature than the other component or components at a temperature sufficient to soften said fiber component and thereby bind the various fiber components together to form a stable and substantially uniform filter element.

Abstract: A device for measuring and recording spontaneous blood platelet aggregation in platelet-rich citrated blood plasma comprising a photometer having a source of light, a photo cell, a light filter and a rotating disk cuvette for receiving the platelet-rich citrated plasma to be tested.