Gov. Jon S. Corzine was breathing on his own again Friday after doctors removed a breathing tube he'd been using since being critically injured in a car accident April 12, his spokesman said.

Corzine broke a leg and several bones in his chest, including 11 ribs, in the collision on the Garden State Parkway. He was placed on a ventilator to ease the pain of breathing, doctors said.

Breathing unassisted moves Corzine closer to having his condition upgraded. He has been listed as critical but stable since he was brought to Cooper University Hospital last week.

Doctors removed the breathing tube at about 12:25 p.m. Friday, spokesman Anthony Coley said.

Corzine was able to speak when he arrived at the hospital, before the breathing tube was inserted. Once on the ventilator, the 60-year-old former investment banker could not speak but was able to communicate by nodding, doctors said.

Though breathing on his own is a major milestone, it was not immediately clear when Corzine would be able to resume his official duties. Doctors said it could take six months before he's able to walk without a cane or walker.

State Sen. President Richard J. Codey, also a Democrat, is serving as acting governor.