In section 3, when Marlow returns the "sepulcher city," he describes his health as follows:
I was not very well at that time. I tottered about the streets- there were various affairs to settle- grinning bitterly at perfectly respectable persons. I admit my behavior was inexcusable, but then my temperature was seldom normal in these days. My dear aunt's endeavors to "nurse up my strength" seemed altogether beside the mark. It was not my strength that wanted nursing, it was my imagination that wanted soothing.
What can the reader infer from Marlow's observation?