Dr. James Mertz, pediatrician to generations of Windward O'ahu children for more than 40 years, would give a single page of "dos and don'ts" instructions to nervous parents of newborn babies.

His No. 1 "do" was "relax and enjoy your baby." That came before feeding and bathing and safety instructions, before anything else. He loved children, both his own large family and the ones he tended and healed in his calm, gentle way.

In the last days of his life, each of his nine children came to be with him. Six of the nine were at his side when he died on Sunday. He was 78.

Mertz retired in 2002 at age 74, reluctant to be leaving his beloved Kailua practice but enthusiastic about relaxing and enjoying his grandchildren. He and his wife, Elizabeth, moved to Lincoln, Calif., near Sacramento, to be near son Bob, a neonatalogist, and his children. Eight of the Mertz kids live in cities across the country. Two are doctors, one is married to a doctor, one is a lawyer, another a ballerina with the American Ballet Theater in New York.

His health started to decline during the holidays, and he suffered from deteriorating lung function. Rather than worry about himself, foremost on his mind was his family.

"Being a doctor, he warned us that the end was near," said son Andy, the only Mertz sibling who still lives Hawai'i. "But he didn't want us to call anyone and get people worried."

It was this way when he left his longtime practice in Kailua. He didn't want anybody to make a fuss about him. In defiance of his orders and almost behind his back, his office staff and many of the families of his patients organized a big "aloha" party for him at Kailua Beach Park.

"He kept saying, 'No need,' but the day of the party, he loved it," Andy said. "It was very special for him."

James L. Mertz was born in Trinidad, Colo., on April 4, 1928, exactly six years to the day after his only brother, Bob. He graduated from Cornell Medical School, and during World War II served in the National Health Service on Indian reservations. When he married Elizabeth Holde in 1970, he already had five kids from his first marriage. Elizabeth helped raise them and together, they had four more additions to the Mertz brood.

Even with all those children at home to look after, he was unfailingly available to everyone else's kids. "I try to see everybody and anybody," he once said. "I'm flattered they want to come see me."

That meant giving out his home telephone number, making follow-up phone calls well into the night, and making time to see patients on the day they needed to be seen.

"He was the hardest-working man I've ever known," says Andy. "Any hour of the day and night, he'd answer the phone. Women don't give birth according to a schedule. In just a few minutes, he'd be out of bed, get in the car and heading to the hospital."

He still made it a point to have family dinners every night with as many of the kids gathered at the big table as possible.

"We had family discussions every night. He was always wide open to ideas. It was important to him for us to be able to talk and express ourselves," Andy remembers. This is why, he says, among the siblings, political views range from "Strong conservative to strong, strong liberal to couldn't care less."

In the last few weeks of his life, Mertz's children took turns helping with his care. When Andy was in California with his sister Nancy, he said his father was mostly concerned about making sure they were OK.

"He said, 'If I pass away while you're taking care of me, I want you to know it wasn't your fault. Know this in your heart, your mind, your very being.' He was getting weaker, but he was so forceful when he said that. It was a real chicken-skin moment."

Mertz didn't want a memorial. He didn't want flowers or a service or any of that sort of thing. But if his patients and their families felt moved to do something, Andy thinks his father would probably like donations to go to his beloved Rotary Club of Windward O'ahu, where he was a member for over 30 years. But he wouldn't ask for such a thing, Andy says. He wouldn't want anyone to make a fuss over him.

Reach Lee Cataluna at lcataluna@honoluluadvertiser.com.