To sights and sounds and events which required action, he responded with lightning-like rapidity.

Quickly as a husky dog could leap to defend from attack or to attack, he could leap twice as quickly.

He saw the movement, or heard sound, and responded in less time than another dog required to compass the mere seeing or hearing.

He perceived and determined and responded in the same instant.
In point of fact the three actions of perceiving, determining, and responding were sequential; but so infinitesimal were the intervals of time between them that they appeared simultaneous.

His muscles were surcharged with vitality, and snapped into play sharply, like steel springs.