Abstract: An automatic pipetter utilizing a syringe having several openings at its end. A different tubing segment connects with each of these openings and extends into different vials of liquids. Of these vials, one contains a buffer solution generally used in appreciably greater quantities than the others. Another vial receives the liquids from the syringe. As a stepping motor partially withdraws the piston from the syringe, a tube leading to a vial with unmeasured liquid is open. When the stepping motor reinserts the plunger into to the syringe, the tube leading to the receiving vial becomes open while the other tubes remain closed. The tubing segments extending between the syringe and the vials include three sections. The section closest to the syringe, formed from polyimide, undergoes a minimal change in its volume notwithstanding the negative and positive partial pressures exerted by the piston.