Half a century ago scientists discovered hot vents on the sea bed that were home to organisms living happily in conditions that, until then, had been thought inimical to life.
Nekhludoff saw that there was something inimical to him in her, which stood guard, as it were, over her as she was now, and prevented him from penetrating into her heart.
In other words, Mr. Dimmesdale, whose sensibility of nerve often produced the effect of spiritual intuition, would become vaguely aware that something inimical to his peace had thrust itself into relation with him.