Synthesized answer
The provided passage does not contain information about unanswered questions regarding the organ of the soul. It only includes the title of the work, the author, a category, and the page number [110]. Therefore, I cannot answer what questions remain unanswered based on this passage.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: Über das Organ der Seele by Samuel Thomas von Soemmerring Categories: Brain Pages: 110