Cuddy is next on House's list of people to get drugs from. He makes her a deal: he'll father her child if she gives him some precious, precious Vicodin. Cuddy is impressed that the Cottages managed to stand up to House's orders. "Yes, their cowardice is inspiring," House agrees. Hee hee hee. Cuddy states the obvious: if the Cottages had written House a prescription, then it would have looked like House had intimidated his employees and gotten him in even more trouble. Cuddy, on the other hand, is House's employer, so she doesn't have this problem. She writes him the prescription, saying that if House doesn't get any drugs, it'll look like he doesn't really need them, which will make Shitter's case stronger. House pronounces Cuddy a "genius" in spite of her cleavage (since we all know that big boobs drains some of the brain's blood supply, thus making well-endowed women stupid), and grabs for the scrip before she can change her mind. Doing so, House winces and has trouble moving his right arm, which does not go unnoticed by the selectively observant Cuddy who didn't notice that House got a new cane. He claims he pulled a muscle training for the Pants Off Dance Off, which I don't think it's fair to mention without letting us see. Cuddy thinks this is another one of House's psychosomatic pains, and asks him what's recently changed in his life to cause it. House has one of his trademark epiphanies, grabs the scrip with his good arm, and takes off.
The Cottages report that House was right about the fungus after all: the spots were abscesses from aspergillus. Good thing they did that test and didn't just assume it was brain cancer, eh? So they know what's wrong with Jack, but they still don't know how he got it. House, of course, has the answer: Jack has a genetic defect in his immune system that has only come forward now because of all the emotional stress Jack's been under with his parents dying. That seems...really far-fetched. But anyway, they can figure out which genetic immune-system defect Jack has based on the infections he's gotten so far, since certain parts of the immune system are especially susceptible to certain infections. While they're doing that, Wilson walks in, needing a Cottage for prescription-writing duties. He's out of luck, though, since House can't spare anyone while his patient is an hour away from death. Wilson storms out without another word. Ha ha ha! He's so weak. If you let people treat you like a doormat, you get treated like a doormat. House and the Cottages narrow Jack's disease down to four possibilities, but Chase points out that genetic testing takes time they don't have. That's okay! House knows another, quicker way to get his answer" he'll expose Jack to the infections each immune disease is most susceptible to and see which infection affects him first. This really only makes sense if all the immune-system problems are equally susceptible to all the related infections, but whatever.