Victor speaks in two places about his methods of collecting body parts (chapter 4). Initially he does so to learn about anatomy and physiology. Once he decides that he can and should animate a living being, he sets about collecting the materials.
In the first phase, rather than just observe dead bodies, he resolves to study “the natural decay and corruption of the human body.” He gets “bodies deprived of life” from churchyards, and studies the decay in bodies that were now just “food for the worm.” He also goes to “vaults and charnel-houses,” often doing his studies on site. As he studies decomposition and the effects of “worms,” a category that seems to include bacteria, Victor develops an emotional attitude toward these processes:
I saw how the fine form of man was degraded and wasted; I beheld the corruption of death succeed to the blooming cheek of life . . .
In this phase and after he decides he can pursue regeneration, what interests him is the change from life to death, and death to life . . . ” Once he settles on his mission, realizing he will need a large number of parts, he goes to nature’s “hiding-places,” including returning to charnel houses. While the reader understands from this narrative that Victor is collecting bodies and body parts, one phrase is particularly troubling:
Who shall conceive the horrors of my secret toil as I dabbled among the unhallowed damps of the grave or tortured the living animal to animate the lifeless clay?
Mary Shelley never clarifies what Victor means by “tortured the living animal . . . ” He may be referring to a nonhuman animal that he regarded as similar to humans, on which he experimented to understand its functions. But it is possible that Victor took one or more living persons for his experiment—perhaps to remove and transplant the heart, brain, or other essential organ.