Thank you so much ,I got it

http://www.finedictionary.com/Nepenthe.html Nepenthe was a drug (maybe mythical) that removes bad memories. There may be more clues in the context of the passage you are quoting, but to me it sounds like he is using poetic language to say that when he becomes restless, he drinks "nepenthe" (perhaps being a metaphor for alcohol) to forget his troubles. Actually, I found a reference to the full passage online: ""I have only run up to town for a week or two before leaving for another spell in Sardinia. I am getting restless again, and there flow the waters of Nepenthe. But the question is: How are you?"" So the speaker is saying that the "waters of nepenthe" flow in Sardinia, by which he means that he goes there to forget his troubles.

So I had to look this up, because I've never heard the word "Nepenthe" before, but it seems like it's referring to a drug that helps take the pain away. In this context it could either be a metaphor, as in he's getting restless and thinking about doing Nepenthe, or he is literally referring to flowing waters that is Nepenthe. It is most likely a metaphor based on the context.