Scientist injecting half of mice in upper body (7)
I believe the answer is:
chemist
'scientist' is the definition.
(I know that chemist is a type of scientist)
'half of mice in upper body' is the wordplay.
'half of' suggests halving the letters.
'in' indicates putting letters inside.
'upper body' becomes 'chest' (I am not sure about this - if you are sure you should believe this answer much more).
'mice' with half the letters taken is 'mi'.
'mi' placed inside 'chest' is 'CHEMIST'.
'injecting' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for chemist that I've seen before include "Pharmacist, say" , "drugs supplied by me?" , "Drug store" , "Pharmacist, apothecary" , "Seller of medications" .)