The day was hot.
His massive coat was a burden.

Life was growing more of a problem than of old it had been.

Also, from time to time, lately, his heart did queer things that annoyed Lad.

At some sudden motion or undue exertion it had a new way of throbbing and of hammering against his ribs so violently as to make him pant.
Lad did not understand this.

And, as with most things he did not understand, it vexed him.