What is most likely the reason the author included part M. Waldmans lecture on modern chemistry in the narrative rather than just describing it?

In volume 1, chapter 2, Victor Frankenstein describes his time at the university. It is here that he becomes interested in "the elixir of life" and "the philosopher's stone," which are basically theoretical keys to immortality. Victor is drawn to these ideas, having recently suffered the sudden loss of his mother to illness. He becomes interested in alchemy, an outdated scientific field, as well. M. Waldman's lecture in chapter 2 is a source of inspiration for Victor; having the lecture quoted rather than simply summarized by Victor lends it a greater power since we know these are the exact words that motivated Victor's fateful project.
Waldman recognizes that "the elixir of life is a chimera" but likens modern scientific practices to "perform[ing] miracles." Waldman says:

They penetrate into the recesses of nature, and show how she works in her hiding places. They ascend into the heavens; they have discovered how blood circulates, and the nature of the air we breathe. They have acquired new and almost unlimited powers.

This notion that scientists are all-powerful appeals to Victor, but Victor takes Waldman's words to an extreme. Although we can see why Victor was inspired by this lecture, the reader can also tell that Waldman's intention was not to spur a project like Frankenstein's, which the novel ultimately implies is totally unnatural. While Waldman sees the scientist as immensely powerful, he probably did not expect one of his pupils to attempt to actually "play God" by creating life on his own.
Later, Victor visits Waldman in his office, and although Waldman is flattered to have Victor's admiration and attention, he warns Victor against committing too readily to one specialized field. It is clear from the chapters that follow that Victor does not follow his mentor's advice when he launches himself single-mindedly into the pursuit of the very "elixir of life" that Waldman told him does not exist.