Their idea of a daring change, he said, is to move north of 86th Street or to a side street off Park or Fifth Avenues.

He carries a black doctor's bag along Park and Fifth Avenues, where he makes house calls.

Open houses have long been prohibited at many of the city's plum buildings on Park and Fifth Avenues.

After the turn of the century the houses were declining with age, even as luxury development pushed out from Park and Fifth Avenues.

"I was all set to deliver it to Park or Fifth Avenue, where she lives," Mr. Topping said.

His farm occupied what is now 68th to 74th Streets between Park and Fifth Avenues.

The district includes parts of blocks in the East 90's between Park and Fifth Avenues.

Most buildings on Park and Fifth Avenues do not have summer rules, Ms. Lenz said.

Mr. Guterman said he and his wife are looking for a five-bedroom apartment on Park or Fifth Avenues.

"But ironically doctors are still finding a shortage in the prime area between Park and Fifth Avenues."