It was rather the long exposure and the overexertion of mind and body during the evening and night.

He had simply collapsed beneath the strain.
But an old army man has said: "Give me a soldier of eighteen or twenty.

In a single day he may not march quite so far as a more mature man or carry quite so much weight.

He will go to sleep each night dead to the world.

But in the morning he awakens a new man.