Talking to Nelly, Heathcliff uses hyperbole to convey his hatred of Edgar Linton:
Had he been in my place, and I in his, though I hated him with a hatred that turned my life to gall, I never would have raised a hand against him. [...] I never would have banished him from her society, as long as she desired his. The moment her regard ceased, I would have torn his heart out, and drank his blood! But, till then—if you don’t believe me, you don’t know me—till then, I would have died by inches before I touched a single hair of his head!
Nelly has been warning Heathcliff that another hostile meeting between him and Catherine's husband Edgar would be too great a shock to Catherine's fragile health. Here, Heathcliff admits that he'd love to kill Linton outright, but refrains for as long as Catherine holds any regard for him. His violent use of hyperbole conveys both his absolute hatred for Linton—"I would have torn his heart out, and drank his blood!"—and his loyalty to Catherine.
As vicious as Heathcliff can be, this language is clearly exaggerated for shocking effect. It also reinforces that even though he (probably) wouldn't drink someone's blood like a vampire, he's cruel, always potentially violent, and essentially a horrible, untrustworthy person. Also, his claim that he would practice restraint until "the moment" Catherine stopped loving Linton just makes his cold-blooded hatred seem more monstrous; though he intends to show how much he cares for Catherine, the hyperbole suggests that he could switch from harmless to murderous in a split second—behavior that's more befitting of a predator than a human being.
As Heathcliff anticipates death and reunion with Catherine, he hyperbolically compares her to both a devil and "heaven."
In Chapter 29, Heathcliff tells Nelly how strongly he senses his beloved Catherine's spirit near him, yet he can't see her. This is such a torment for him that he calls Catherine a "devil" whose "tortures" are "infernal" (hellish):
I ought to have sweat blood then, from the anguish of my yearning, from the fervour of my supplications to have but one glimpse! I had not one. She showed herself, as she often was in life, a devil to me! And, since then, sometimes more, and sometimes less, I’ve been the sport of that intolerable torture! Infernal—keeping my nerves at such a stretch, that, if they had not resembled catgut, they would, long ago, have relaxed to the feebleness of Linton’s.
Catgut is tough string or cord that's made from dried animal intestines (like those of sheep, hogs, or cattle). Basically, Heathcliff's nerves are extremely strong, unlike his feeble son's. Even so, Catherine's teasing presence has kept Heathcliff's nerves intolerably taut for years. She is a "devil" because she has the ghostly power to toy with Heathcliff, letting him feel her closeness but not see or touch her, making him long for death and reunion with her.
While this is Heathcliff's typical hyperbole (he wouldn't literally sweat blood, for example), his comparison of Catherine to a "devil" and the sense of her nearness to "torture" shows how desperately and obsessively he still yearns for Catherine, some 18 years after her death. It also suggests that his passion for her is disturbingly tangled up with resentment and even hatred.
Later, in Chapter 34, Heathcliff gives Nelly directions regarding his funeral:
No minister need come; nor need anything be said over me—I tell you, I have nearly attained my heaven; and that of others is altogether unvalued, and uncoveted by me!
Nearing death, Heathcliff has almost attained "his heaven"—that is, Catherine. Though, as the previous passage shows, he's just as inclined to call her a devil. At the same time, Heathcliff shockingly says he doesn't need a Christian burial, implying that Catherine is all the blessing he'll require as he enters the afterlife. Essentially, then, Catherine is Heathcliff's deity, even if she takes a cruelly unattainable form while Heathcliff remains alive.
As Heathcliff anticipates death and reunion with Catherine, he hyperbolically compares her to both a devil and "heaven."
In Chapter 29, Heathcliff tells Nelly how strongly he senses his beloved Catherine's spirit near him, yet he can't see her. This is such a torment for him that he calls Catherine a "devil" whose "tortures" are "infernal" (hellish):
I ought to have sweat blood then, from the anguish of my yearning, from the fervour of my supplications to have but one glimpse! I had not one. She showed herself, as she often was in life, a devil to me! And, since then, sometimes more, and sometimes less, I’ve been the sport of that intolerable torture! Infernal—keeping my nerves at such a stretch, that, if they had not resembled catgut, they would, long ago, have relaxed to the feebleness of Linton’s.
Catgut is tough string or cord that's made from dried animal intestines (like those of sheep, hogs, or cattle). Basically, Heathcliff's nerves are extremely strong, unlike his feeble son's. Even so, Catherine's teasing presence has kept Heathcliff's nerves intolerably taut for years. She is a "devil" because she has the ghostly power to toy with Heathcliff, letting him feel her closeness but not see or touch her, making him long for death and reunion with her.
While this is Heathcliff's typical hyperbole (he wouldn't literally sweat blood, for example), his comparison of Catherine to a "devil" and the sense of her nearness to "torture" shows how desperately and obsessively he still yearns for Catherine, some 18 years after her death. It also suggests that his passion for her is disturbingly tangled up with resentment and even hatred.
Later, in Chapter 34, Heathcliff gives Nelly directions regarding his funeral:
No minister need come; nor need anything be said over me—I tell you, I have nearly attained my heaven; and that of others is altogether unvalued, and uncoveted by me!
Nearing death, Heathcliff has almost attained "his heaven"—that is, Catherine. Though, as the previous passage shows, he's just as inclined to call her a devil. At the same time, Heathcliff shockingly says he doesn't need a Christian burial, implying that Catherine is all the blessing he'll require as he enters the afterlife. Essentially, then, Catherine is Heathcliff's deity, even if she takes a cruelly unattainable form while Heathcliff remains alive.