He went home dead-beat, is very irritable, off his food, can't sleep, and swears cantankerously that there's nothing the matter with him,--the usual symptoms.

Can you throw any light on it ?" "Certainly not," I replied rather sharply.
Cliffe said "Umph!" in his exasperating professional way and proceeded to feel my pulse.
"I don't quite see how Friday's mild exertion could account for YOUR breakdown, my friend," he remarked.
"I'm so glad you confess, at last, not to seeing everything," said I.
I was fearing this physical reaction in Sir Anthony.

It was only the self-assertion of Nature.

He had gone splendidly through his ordeal, having braced himself up for it.

He had not braced himself up, however, sufficiently to go through the other and far longer ordeal of hiding his secret from his wife.