A method is proposed for introducing an accurately dosable amount of mercury into the discharge vessel of a lamp, in particular into a straight fluorescent lamp, wherein both sides of the discharge vessel are connected to a lamp receptacle; and the discharge vessel is charged with a gas stream via the lamp receptacle and is filled, moreover, with a predetermined amount of mercury via a mercury introducing channel. Furthermore, it is provided that during or after dosing the amount of mercury to be introduced, the mercury is brought in a dosed volume in the form of a single, coalescing drop, and then in a fill step the entire amount of mercury to be introduced is transported into the discharge vessel, while still maintaining the previously formed drop. To this end, there is a change-over mechanism, which in the preparation step guides the gas stream past the drop via a bypass channel and in a fill step blocks the bypass channel in such a manner that, while the bypass channel is blocked, the gas stream is guided over the dosed volume and drags the drop along with it into the discharge vessel.