This paper considers the influence of several parameters on the current through a nematic liquid crystal cell. The dependence of the current on the average field

, where

is the voltage and

the thickness of the nematic film, does not prove the existence of Schottky emission or field-assisted dissociation. We have measured the electric field distribution in a thick cell containing the nematic. There is an appreciable cathode fall where the electric field is much higher than the average value. Our experiments, made under dc conditions, suggest that the theory of unipolar-injection-induced instability is correct.