A system and method are provided for selectively dosing and dispensing a predetermined liquid material in and from a pre-dispensing measuring sight glass container vessel, wherein a housing is disposed to receive a pressurized fluid stream, to provide an intermediate measurement and storage vessel for the liquid material and to provide a selectively operable valve assembly that is disposed in a flow path defined in the housing. The housing includes an inlet, an outlet, and an intermediate portion extending therebetween, which is formed with an admission port for admitting the predetermined liquid material. The valve assembly is disposed between the housing's inlet and outlet, and may be selectively operated to fill the sight glass container from the source container; or, to dispense the liquid material from the sight glass container; or, to clean the sight glass container; or, to just provide a flow of the pressurized fluid without any liquid material. At no selection or operating condition can liquid material from the source container be dispensed without first being measured into the sight glass container.