Abstract: There is disclosed a wound dressing comprised by an assembly of microfungal fibres which have been treated with alkali to expose chitin and chitosan. The fibres may be derived from hyphae or from sporangiophores. The assembly may include other fibres, may be bleached and incorporate other additives such as silver as an anti-bacterial agent.

Abstract: A knife of the kind having a blade (14, 43) and a handle has an extendible and retractable blade edge guard (16, 45). When the blade (14, 43) is extended, any violent movement of the knife with the cutting edge in a leading attitude acts inertially to disengage a detent (27, 55) from a recess (28, 57) in the guard (16, 45) so that a tension spring (17, 46) quickly extends the guard (16, 45) into its projecting, operative position to guard the blade edge (21, 50) and prevent at least serious injury. When the blade carrier (13, 42) is fully retracted, its engagement with a part (31, 58) of the guard (16, 45) causes that also to retract and be engaged again by the detent (27, 55) due to spring-bias.