A system for loading plural cannulae with a substance that is to be injected into living tissue. This invention provides an efficient means of providing plural substance-filled cannulae for surgical procedures, such as vertebral augmentations. The system includes a mixing and delivery system, including a manifold. The manifold includes a housing with a plurality of channels that route the flow of the mixed substance from a single central channel to multiple sub-channels for the simultaneous filling of attached cannulae. The manifold also includes valves that regulate the flow of the substance out of the manifold. The open/closed states of these valves are inherently set as a function of the presence/absence of cannulae. A cartridge/plate releasably holds the multiple cannulae to the manifold. The release of the cartridge/plate results in the simultaneous release of the substance-filled cannulae from the manifold.