Inducer

From TARDIS Index File, the free Doctor Who reference.

An Inducer is a machine used to 'seed' humans who have taken the Adipose pill. It can also receive messages.

Matron Cofelia manages to 'seed' a million humans. The Doctor manages to overide the Matron's Inducer with a second one inside a cupboard. He did this by attaching two capsule-like-necklace's to the machine. The Doctor's Inducer recieved a message from the Adipose First Family and worked out that they would kill their accomplice, Matron Cofelia. (DW: Partners in Crime)