An apparatus for delivering anaesthetic to human or animal patients. The apparatus is an anaesthetic machine which is arranged to mount components of an anaesthetic delivery circuit, and which includes a collector arrangement in the form of a manifold having a plurality of inlets and outlets. The manifold enables a reduction in the number of tubes connecting the various components in an anaesthetic system, which are normally required in prior art anaesthetic machines. The manifold also includes an arrangement which provides a Venturi effect on gas flow, and enables a pressure gauge to be mounted out of a patient breathing circuit. The machine is preferably portable.