Power of Desire in McTeague

In McTeague, lust and greed are the two distinct themes that guide McTeague throughout the novel. I find it interesting that Norris uses these two themes as they seem to be close cousins, having similar effects on people. In the early part of the novel McTeague is driven by lust. When he has Trina in his dentistry chair, the man displays not only a want to have her, but a need. This lust is our first indication that McTeague is a person incapable of suppressing his own desires. Lust is demonstrated again, later on, when McTeague finally kisses Trina. Here, he let's out an almost primordial yell of "I've got her," showing the insatiable power lust engulfs him with.  With his sexual desires presumably taken care of,  McTeague seemingly channels his lust into greed as the novel moves forward. It becomes fairly obvious that McTeague's greed irrevocably changes the man, as he becomes more and more fortune-hungry. Norris compels his argument by making McTeague as mindless as he does. I don't think this novel works as well if McTeague is presented with any capacity for wit or intellect. Instead McTeague is borderline an animal of his landscape. He is controlled by his instincts and shows no way of breaking free of their grip.