Abstract: A re-entrant cannula device for use in the proximal duodenum and/or the site to terminal ileum of, for example, sheep and pigs, which comprises a casing of resilient material and a cylindrical plug cock which is pressed into the casing and has two digesta passages extending through the cylindrical plug cock along separate, isolated, curved paths. The casing has two, splayed intestine connectors and the cylindrical plug cock is rotated, by a connector tube in one digesta passage, from a "maintenance" position wherein digesta flows through one connector, along one digesta passage in the cylindrical plug cock and back to the intestine through the other connector, to a "collection" position where digesta flows from one connector along one digesta passage for collection and is returned to the intestine along the other digesta passage and connector back to the intestine.

Abstract: The middle ear space is vented through the tympanic membrane by a piece of porous plastic material positioned to extend through the tympanic membrane. The pore size is in the range of 5 to 25 micrometers in diameter to effectively prevent water passage and permit tissue ingrowth a few pores deep from the tympanic membrane into the side walls of the vent. The vent is generally cylindrical in shape provided with a section of reduced cross-sectional area intermediate its ends, which section engages the tympanic membrane when the vent is in position.