Apparatus for the respirating of patients, with a line system for the flow-through of respiratory gas with connections for the patient, for the supply of components of the gas and for the discharge of components of the gas, characterized in that the line system is built up of a first and a second, substantially plate-shaped, part, with each an inner surface and an outer surface, which are intended to be placed with their inner surfaces against each other, while in the inner surface of at least one of the parts a canal with a longitudinal side that is open toward the inner surface is provided, such that during placement thereon of the inner surface of the other part the open side of the canal is covered and a flow-through pathway is formed through which respiratory- or anaesthetic gas can be fed.
