There is a telling moment of situational irony in Chapter 3, when Montgomery defends M'ling from the drunken ship captain's abuse:
I could see that Montgomery had an ugly temper, and I saw too that this quarrel had been some time growing. “The man’s drunk,” said I, perhaps officiously; “you’ll do no good.”
Montgomery gave an ugly twist to his dropping lip. “He’s always drunk. Do you think that excuses his assaulting his passengers?”
Montgomery has a real point here. The captain's drunkenness does not excuse him from treating his passengers well. It certainly is not an excuse to physically assault anyone, as he does M'ling. But Montgomery's principles are inconsistently applied. He has already spoken cruelly to M'ling, and there have been signs that he is physically abusive as well. It is later revealed that Montgomery habitually gets drunk and beats M'ling. It is ironic that Montgomery can recognize the captain's behavior as unjust and unacceptable when he is not nearly so critical of his own behavior.
Then again, Montgomery's indignation at the captain's drunken violence toward M'ling may not reveal a lack of self-awareness so much as deep disgust with his own behavior. Montgomery struggles to moderate his drinking and his violence. He may be so intent on disrupting the ship captain's mistreatment of M'ling precisely because he can't disrupt the abuse he perpetrates himself. Regardless of how self-aware Montgomery is, the moment also reveals that he is possessive of M'ling. Montgomery does not see M'ling as just another passenger on the boat. He behaves in vastly different ways toward M'ling and toward Prendick. Montgomery is not angry that his servant is being mistreated, but rather that someone else is treating his servant as poorly as he treats him. Montgomery isn't as powerful as Moreau on the island, and he likes having total power over at least one being. M'ling is that being for him.
In Chapter 15, Prendick learns more about the Beast Folk now that Moreau has described to him how they came to be. There is situational irony in the way Moreau and Montgomery talk about the Law as a restraint on the Beast Folk's behavior:
Montgomery told me that the Law, especially among the feline Beast People, became oddly weakened about nightfall; that then the animal was at its strongest ; a spirit of adventure sprang up in them at the dusk, they would dare things they never seemed to dream about by day.
Montgomery and especially Moreau are treating the Beast Folk (or "Beast People," as Prendick refers to them here) like scientific specimens. Moreau thinks of himself as a rigorous scientist, committed to discovery above all else. He closely analyzes the effect of the Law on the Beast People's behavior under different circumstances, such as at nightfall. It is ironic, however, that for all his careful attention, Moreau fails to turn his scientific eye on himself to see how he has caved to his own animal impulses.
Moreau thinks of himself as, at the very least, on his way to being superior to animal impulses. He is obsessed with ideal man and with engineering the most advanced form of humanity. At its most advanced, Moreau believes, humanity should be able to overcome the biological drives that make animals behave the way they do. This is what he begins trying to achieve with the Beast Folk by imposing the Law. Darwinian evolution had recently become popular as a scientific explanation for how complex life forms, including humans, came to exist. Moreau is impatient; whereas Darwinian evolution takes place over thousands, millions, and billions of years, he wants to see humanity at its most advanced now, in his lifetime. He exiles himself from society to see if he can "perfect" humanity faster than Darwin's evolution can.
But without the law of society governing his behavior, Moreau too is like an animal under cover of night, doing things he would never dream of doing in the light of day. He tortures animals, even when he believes them to be partly human. He establishes a dictatorship, utterly failing to consider the rights of the Beast Folk. He even drugs Prendick when he first arrives on the island, demonstrating that he will stop at nothing to maintain control of the situation within his little kingdom. Moreau watches the Beast Folk closely for law breaks under the premise that everything will get out of hand if the Law is threatened. Meanwhile, he is the one who truly needs laws to govern his behavior.
