Never have two settings been more different than the laboratory and neighboring boudoir in "The Birthmark." Let's take a look at the text:
she found herself breathing an atmosphere of penetrating fragrance […] The scene around her looked like enchantment. Aylmer had converted those smoky, dingy, sombre rooms, where he had spent his brightest years in recondite pursuits, into a series of beautiful apartments not unfit to be the secluded abode of a lovely woman. The walls were hung with gorgeous curtains, which imparted the combination of grandeur and grace that no other species of adornment can achieve; and as they fell from the ceiling to the floor, their rich and ponderous folds, concealing all angles and straight lines, appeared to shut in the scene from infinite space. For aught Georgiana knew, it might be a pavilion among the clouds. And Aylmer, excluding the sunshine, which would have interfered with his chemical processes, had supplied its place with perfumed lamps, emitting flames of various hue, but all uniting in a soft, impurpled radiance. (29)
The first thing that struck her eye was the furnace, that hot and feverish worker, with the intense glow of its fire, which by the quantities of soot clustered above it seemed to have been burning for ages. There was a distilling apparatus in full operation. Around the room were retorts, tubes, cylinders, crucibles, and other apparatus of chemical research. An electrical machine stood ready for immediate use. The atmosphere felt oppressively close, and was tainted with gaseous odors which had been tormented forth by the processes of science. The severe and homely simplicity of the apartment, with its naked walls and brick pavement, looked strange, accustomed as Georgiana had become to the fantastic elegance of her boudoir. (57)
Not only do the physical details of each room scream "contrast," but, more importantly, the mood or atmosphere of the two rooms is completely opposite. The boudoir, we see, is the realm of the spiritual – freed from the earth and from all humanly imperfections. But the lab is just the opposite; it reeks of earthy smells and is literally smudged with soot. The boudoir is the dwelling place of all Aylmer's lofty, spiritual aspirations – everything he wants to accomplish as a scientist. But the lab stinks of his failures, of the reminders that he is mortal and cannot compete with Nature on a scientific scale.
There's also a bit of male/female dichotomy going on here; the boudoir is meant for Georgiana, the woman, while the lab is where the men work. It is significant that Aylmer puts his wife in the boudoir and doesn't want her to leave, imagining that he can "draw a magic circle round her which no evil might intrude" (29). This attempt to shelter Georgiana is both misguided and impossible; just as his attempts to remove the birthmark are really an attempt to remove her humanity, so Aylmer's desire to shelter her from evil is a desire to shelter her from her own humanity.
It is also significant that the lab room and the boudoir are right next to each other, separated only by a wall. In their "Character Analyses," we talk about Aylmer and Aminadab as representative of the two poles of man's nature – one half spiritual, the other half earthly. The two rooms basically represent these two different aspects of man's character. They could not be more different, but yet they are forced to coexist in close proximity.