As with many of the films in which he appears, the centerpiece of Island of Lost Souls is Laughton's performance. Dr. Moreau is a daunting acting challenge; he must be cultured and intelligent, slowly revealing his delusions of godlike power while retaining the veneer of a reasonable man of science. Laughton's crafty, slippery Moreau is unsettling and memorable.

Equally unsettling are the victims of Moreau's experiments. The filmmakers took great care to establish these beasts as more than mere extras in makeup. The turning point of the film comes when they realize that ritual of the Law, with its congregational response of "Are we not men?" is meaningless. Because these characters have been brought to life, particularly by Bela Lugosi in one of his more overlooked roles as the Sayer of the Law, this moment is powerful and not a little frightening. Their access of insight demonstrates that the real monster is Moreau.

The film does have a certain weakness, in that all the folks from off the island are terribly bland compared to the creepy Moreau, his conflicted assistant, and their disturbing creations. Arlen is required to play a standard, square-jawed male archetype; Hyams is must wear a sun hat, worry, and scream. This delineation between the islanders and the visitors is deliberate, but it oversimplifies Edward Parker and his reactions to Lota and Moreau.

Island of Lost Souls is the first of four renditions of H.G. Wells' milestone novel The Island of Doctor Moreau. And the haunting, gothic art direction and cinematography, the simple poignancy of the victims' plight, and Laughton's commanding performance combine to make this the definitive realization of the fable of Dr. Moreau.