His pale face was clean-shaven, save for a thin and wiry grizzled moustache, which cast into stronger relief the deep-set, hawk-like eyes and the acute, intense, intellectual features.

In some respects, his countenance reminded me often of Dr.Martineau's: in others it recalled the knife-like edge, unturnable, of his great predecessor, Professor Owen.

Wherever he went, men turned to stare at him.

In Paris, they took him for the head of the English Socialists; in Russia, they declared he was a Nihilist emissary.

And they were not far wrong--in essence; for Sebastian's stern, sharp face was above all things the face of a man absorbed and engrossed by one overpowering pursuit in life--the sacred thirst of knowledge, which had swallowed up his entire nature.
He WAS what he looked--the most single-minded person I have ever come across.