He had refused utterly to enter into any connected conversation and had been restless and erratic to a degree.
"Too muchy moon-devil," according to Li Ho.

That very afternoon he had met them coming down from their talk upon the rocks and the ironic courtesy of his greeting had been little less than baleful.

At supper he had remarked sentimentally upon the flight of time, referring to the nearness of Friday in a way eminently calculated to speed the parting guest.
Friday, at latest, then?
If they were to go they would go on Friday .-- Friday and the full moon.
In the meantime he felt no desire for sleep.

The moon, perhaps?
Certainly there is nothing in the mere business-like prospect of engaging a permanent secretary to cause insomnia.

The professor supposed it was simply his state of health in general.