At the end of The Island of Doctor Moreau, after the protagonist gets off the island, we see that he has developed a sort of revulsion towards other humans:
Then I look about me at my fellow-men; and I go in fear. I see faces, keen and bright; others dull or dangerous; others, unsteady, insincere, — none that have the calm authority of a reasonable soul. I feel as though the animal was surging up through them; that presently the degradation of the Islanders will be played over again on a larger scale. I know this is an illusion; that these seeming men and women about me are indeed men and women, — men and women for ever, perfectly reasonable creatures, full of human desires and tender solicitude, emancipated from instinct and the slaves of no fantastic Law, — beings altogether different from the Beast Folk. Yet I shrink from them, from their curious glances, their inquiries and assistance, and long to be away from them and alone.
The Island of Doctor Moreau, chapter 22: "The Man Alone"
Is this just Prendick suffering from PTSD, or is it meant to imply something about humans in general?