The Interior Department has fired a vetern scientist for writing to one of Secretary Cecil D. Andrus' favorite Frech restaurants, Dominiques's, asking the owner to stop serving rattlesnake steaks.

The scientist, endangered species herpetologist C. Kenneth Dodd, had written to uniform the owner that the snake in question, which hails from Pennsylvania, "is rapidly approaching extinction . . . I respectfully request that (rattlesnake) be removed from your menu."

Though the owner, Dominique D'Ermo, promptly stopped offering rattlesnake, the letter was leaked to the Washington Star's gossip column "Ear."

So mortified was Andrus that, the next day during an outing to Dominique's, he apologized to D'Ermo, following up the personal apology with a written one later.

But it did not end there. Yesterday, Dodd was handed a letter of dismissal that included a four-page list of offenses, all stemming from the offending letter. Included in the charges was the accusation that, because the Star treated the letter "in a cavalier fashion . . . a serious matter was presented . . . as trivial and frivolous to the public.

The list of charges also accused him of using official Interior Department stationery "which . . . could and did mislead the recipient into believing that your letter represented the official position of the Department."

Dodd shaken by the abruptness and severity of the Interior Department's response, conceded yesterday that he may have been a bit overzealous, particularly in using department stationery in writing the letter. But he does not see why he should be fired.

"Even if it is against the rules, most people would get a simple slap on the wrist or a reprimand," he said. "It's been blown all out of proportion."

In the midst of the rattlesnake stew is an ebullient Dominique, whose rattler recipes have catapulted his restaurant into local television, the city's two major newspapers and the highest levels of the Interior Department.

Dominique now sells Texas Diamondback rattler, a species he claims isn't endangered and in fact is better.

"It's a bit fatter," he said yesterday, explaining that he sautees the rattler in a red wine sauce with fresh mushrooms and onions, welling 50 to 75 pounds of it a week.

"People will try anything once," he said in a French accent as thick as his rattler sauce.

Meanwhile, Dodd's plight has brought Washington's wildlife lobby to his defense.

"The real tragedy," said Lewis Regenstein, vice president of the Fund for Animals, "is that a conscientious, competent biologist is being fired for carrying out his duties . . . on the whim of his boss who likes to dine at Dominique's."

An Interior Department spokesman yesterday declined to comment on whether Andrus himself ordered Dodd fired for writing the letter. "The secretary doesn't involve himself in every spell that falls," said public affairs officer Harman Kallaman.

Andrus could not be reached for comment.

Dodd stated in his letter to D'Ermo that biologists have expressed concern about the fate of the Pennsylvania timber rattler. But Andrus, in his letter to D'Ermo, noted that the snake "is not listed as either threatened or endangered under the Endangered species Act, and consequently, there are not prohibitions that I am aware of which would prevent you serving it in your restaurant."

However, according to federal and state authorities, Pennsylvania law prohibits the commerical sale of rattlesnakes. If they were sold and shipped across state lines -- and D'Ermo said he bought the meat from a Pennsylvania game dealer -- the transaction could be a violation of federal laws which ban the interstate shipment of illegally taken game, authorities say.

Dodd, 29, in the past a highly praised GS-12 scientist specializing in reptiles, was called "the most productive branch biologits" in the Fish and Wildlike Service's Office of Endangered Species, according to his annual performance evaluation.

Dodd called the charges "trumped up," and said he plans to appeal the firing. "I'm not even a whistleblower," said the incredulous scientist. "I was just doing my job. It's the damndest thing I've ever seen.

As for Dominique -- now pondering how to unload 15 pounds of illegal Louisiana alligator tail dropped off in his kitchen by an enthusiastic gourmet -- he is truly sorry Dodd got fired. "He seemed like a very nice gentleman," said Dominique. "Eet eez too bad he fell in love with zee snakes."