Why does the narrator comment I was a hospital in myself?

Jerome makes this comment because as a hypochondriac, he already has every disease known to men.... the students (in context) have no need to look further for a source of education.

I thought what an interesting case I must be from a medical point of view, what an acquisition I should be to a class! Students would have no need to “walk the hospitals,” if they had me. I was a hospital in myself. All they need do would be to walk round me, and, after that, take their diploma.