Complex sentence: Early was an inveterate fault-finder and offered biting criticism of his subordinates at the least opportunity; in the reverse case, he was generally blind to his own mistakes and reacted fiercely to criticism or suggestions from below.
Split into simpler sentences: Early was an inveterate fault-finder and offered biting criticism of his subordinates at the least opportunity. He was generally blind to his own mistakes and reacted fiercely to criticism or suggestions from below.