Bioanalyser

From Tardis Wiki, the free Doctor Who reference
The Fourth Doctor uses a bioanalyser in a bid to save Leela's life. (TV: The Face of Evil)

A bioanalyser was a device used to identify poisons. The Fourth Doctor used one left behind by an expedition to a jungle planet to identify the toxins in a janis thorn. In combination with a medikit, this was used to restore Leela from paralysis and save her from death after Calib had used the thorn against her. (TV: The Face of Evil)