Mark Twain said, “It’s easy to quit smoking. I’ve done it a thousand times.

“A man who quit smoking said they told him it would make him a new man. “It did,” he said. “Adolph Hitler.”

 When you smoke you’re in the “deadly and iron clad grip of the nicotine addiction.” So says Joel Spitzer, coordinator of the Stop Smoking Clinic at Rush North Shore Medical Center.

 Last week, 60 of the most cheerful, healthy looking people I’ve seen in one room gathered at Rush North Shore to help Spitzer celebrate his 100th clinic. In 13 years nearly 4,000 smokers have come to the clinics. Fifty-four percent of them have kicked the habit, permanently.

 I don’t know of any program that can match that record.

 Spitzer handed out certificates of achievement to the 60 people, congratulating each on stopping smoking. For each one he calculated the number of cigarettes they have not smoked since they stopped.

 A person who smoked a pack a day and quit two years ago represented 14,600 unsmoked cigarettes.

 The champion in the group, who kicked a five-packs-a-day habit in 1982, would have smoked 325,116 cigarettes since then if he hadn’t stopped. That would be worth about $14,000. The whole room totaled some 4 million.

 I asked two doctors about their experience. “I smoked for 46 years,” said Dr. Andrew Thomson. “I started in college…I thought it was the sophisticated thing to do. Once I was off for two weeks after hypnosis. I figured it was easy. I could stop and start at will. I was wrong.”

 Joel convinced me I was addicted.”

 Dr. Dennis Weber, a dentist, smoked two to four packs a day for 35 years. “Most of the kids I grew up with were smoking at 14,” he said.

 Both doctors regularly come back to the clinic to reinforce their resolve to avoid taking another puff and to give encouragement to people trying to quit.

 The spirit at last week’s meeting was like one big pep rally. Everyone gave a little talk after getting his or her certificate. The group was about evenly male and female, all economic levels, ages mostly 30s and up.

 One woman had been to 13 clinics, was thrown out of the last commercial one, and finally kicked the habit under Spitzer’s haranguing. He’s a nag. After smokers leave the clinic, he keeps in touch with them, with letters, phone calls, and 24-hour availability if they crave a puff and have to be talked out of it.

 “If I hadn’t stopped I wouldn’t be alive today” was the response of many.

 Others:

 “My family thanks me weekly…sometimes daily.”

 “It’s one of the most amazing things in the world that I got unhooked from something that is so terrifyingly addictive.”

 “You mean I haven’t smoked 114,900 cigarettes since I quit? How’d you get that number? It happens to be the exact number of Lotto tickets I’ve bought.”

 “I thank you, my husband thanks you, my mother thanks you, my father thanks you, and my 7-year-old thanks you.” (I thank her too. She used to hide her cigarette when I came into her office in the hospital.)

 “I brought my secretary to the clinic. There were three people in my office, and I knew I couldn’t make it alone. I’m off now, and so is my secretary. The third person in our office, who pooh-poohed us, lost one lung to cancer, then got emphysema. He’s dead.”

 “I’m happy and I never think about cigarettes.”

 One man told about going to a business meeting at Philip Morris. When Spitzer learned he was going to the meeting, he traced him to a Detroit hotel and woke him at 6:30 a.m. to warn him not to take another puff.

 “There were 22 of us around the table at that meeting at Philip Morris,” the former smoker related, “and would you believe it, not a single person smoked.”