The title of this episode is listed as "Preventive Medicine", but it should be "Preventative Medicine".
I can't find it in a preferred source — StudioSystem appears to require a paid account, and I can't find how to get past the marketing on gracenote.com to get to the search

IMDB has it spelled correctly: https://www.imdb.com/title/tt0068098/ep ... t_eps_sn_7 but I can't find it in any other acceptable sources, probably due to age. tv.com has the incorrect spelling, though, but the rules do say it's unreliable…
I can attach a photo of the actual DVD cover if it helps, though.