"I don't think he's forgotten anything he ever knew," his wife confirmed.
And there's a lot to remember.
Rulison worked as an anesthesiologist with the Army Medical Corps in World War II, treating wounded soldiers in the 51st Evacuation Hospital in Europe. He went on to a long career as a general surgeon, then retired and began traveling the world with Jean as a scuba diver and underwater photographer. Together, we watched an old "American Sportsman" episode in which Rulison and "Jaws" author Peter Benchley dive in the Sea of Cortez to study the schooling patterns of hammerhead sharks, and in one scene, Rulison rides a manta ray with an 18-foot wingspan.
These days, the big adventures are history, and Rulison gets around the house with a walker and cane. He has survived a triple bypass, and about 20 years ago, oral cancer spread to his neck. Part of his face was removed, chewing became impossible, and he has existed on pureed foods for two decades.
But he enjoys reading, loves his wife's company, and he has a new cause. Death with dignity. Legislative and ballot proposals have failed previously in the state, but Rulison hopes Californians can be educated to view the option not as suicide, but as an acceptable personal choice.
"I don't want to sit around a nursing home and not know what day it is, or have people come and see me and I don't recognize them," Rulison said. "To me, that's not living."
When he decides he's ready, he will open a safe that contains a vial of methadone, a syringe and a needle. He's been holding on to that drug since he shut down his medical practice in 1976. He will squeeze one shot into each hip, he said, find a comfortable place to lie down, and that will be it. If he is too feeble to manage that on his own, he has arranged for someone to help.
I asked why he would do it that way rather than starving himself. Not eating or drinking will certainly do the job, Rulison said. But why shouldn't we all have the most humane option available to us?
"It's quicker and neater, I think, to do it my way. I'm just eliminating two weeks of starvation. It gets messy toward the end. You get so weak you can't take care of yourself."
There is no trace of fear in his voice.
"I have a rather pragmatic view of life," Rulison said. "To me, we're born, we live, we die and we're recycled into new life."
In his letter to California, Rulison ended with this:
"Perhaps these last encouragements before I myself die with dignity will fall on listening ears."