MTH has got it right. Good grades and good LSATs are the key. There is no "major" for law. Many think that Political Science is the lead-in. However, the two most popular majors for lawyers are English and Economics (last I heard). Caufield is also correct, however, I believe you must pass the regular bar in your state before you can sit for the patent bar, and I also thought your undergrad degree must be in engineering, but I could be wrong on the latter.
Actually, there is no "major" for pre-med, only a series of courses you must take. So, you could be an Econ, take the prereq. of science courses, and take both the medical boards and the bar! Imagine that (actually there are a lot of doctors that have also taken and passed the bar, and visa versa, and in some states you don't even have to go to law school to sit for the bar, all you have to do is meet the OTJ training requirements!)