It's a biblical quote referring, I believe, to Jesus. Thus the statement about truth etc is implicit. It's actually not that bad a motto. Refers to both the civilizing mission, the religious motivation, and the physical location of the school. contrast this to the state of Michigan's motto. It's "Si quaeris peninsulam amoenam, circum spice" literally, "If you seek a pleasant peninsula, look about you!" I mean, there are definitely worse.
As far at the Dartmouth College thing, stop lying, you have a goddamned Med School. you're a university. Get over it.
"Dartmouth College is a private, coeducational university located in Hanover, New Hampshire, in the United States. It is a member of the Ivy League and is one of the nine colonial colleges founded before the American Revolution."http://en.wikipedia.org/wiki/Dartmouth_College