It is shown that, although the mass transfer is complex, the average faradaic current for a dropping mercury microelectrode (DMmuE) behaves very similarly to that of a normal DME, so that the usual analysis procedures can be applied to the polarogram. Owing to the fast mass transport quite large rate constants, up to 0.5 cm s-1, can be obtained in a potential range more negative than usual. The small drop time allows polarograms to be recorded in far less than 1 s, and polarographic maxima will be absent.