Pawn and Two: As <Eyal> has noted, Black is fine after 36...e5.
Fritz indicates the position would actually be slightly in Black's favor: (-.48) (21 ply) 36...e5 37.fxg6+ Kxg6 38.h4 Kg7 39.hxg5 Qc4 40.Qc6, and now Black can play 40...Qd3, 40...Qf7, or 40...Qe6, with each move giving Black a small advantage.
Alekhine stated, that if 36...e5, then 37.Qd5+ Kf8 38.Qc6 Qxc6 39.bxc6 exd4 40. Rxe7 Rxe7 41.Rxe7 Kxe7 42.c7 would win for White.
However, Black can improve on Alekhine's recommendation, 36...e5 37.Qd5+, now Black obtains the advantage by playing: (-.93) (22 ply) 37...Kg7 38.Qc6 Qc8 39.fxg6 hxg6.
In this line Black should not play 37...Kf8?. After 36...e5 37.Qd5+, (-.15) (21 ply) 37...Kf8? 38.fxg6 hxg6 39.Qc6 Qxc6 40.bxc6 Nc5, the position would then be close to equal after 41.Bxe5.
In Alekhine's line, after 36...e5 37.Qd5+ Kf8? 38.Qc6?, Black can then gain the advantage by playing: (-.76) (21 ply) 38...Rc8 39.fxg6 Qxc6 40.bxc6 Rxc6 41.gxh7 Kg7 42.Bxe5+ Kxh7.