Possible Clues:

• Novel character of part-time doctor?
• Dr -- and Mr Hyde
• Stevenson title character
• Noted alter ego
• Cases of jaundice? Kindly, logical doctor's needed here
• Gardening writer with a dark side?
• Character who sings 'This Is the Moment'
• Doctor with an alter ego
• Stevenson physician
• He was his own worst enemy