### Clue: Student in step with former student recalled part of experiment (7)
### Answer: PLACEBO 
 ### Explanation: Definition: part of experiment
 L(the plate displayed by a learner driver) **contained in**(in) PACE(a step;a stride) **plus**(with) **reversal of**(… recalled) OB(abbrev. for "Old Boy";a former student).
Answer: An inactive substance or sham therapy administered as part of a clinical trial;experiment, as a control against which to compare the effects of the real substance or therapy.