 John Amos (I) (qv), who plays Dr. Herbert, gives Dr. Huxtable a  complete physical. When Huxtable is getting on the treadmill, Amos  delivers the line, "Youll go into oxygen debt. If you last long  enough youll go into oxygen bankruptcy." This is the exact same  line Amos delivered in _American Flyers (1985)_ (qv) when he played  Dr. Conrad and administered a similar test to David Sommers.