Louis (Junior) Morton, the 16-year-old Southeast Washington youth who was bitten 3 1/2 weeks ago by one of two deadly Gaboon vipers stolen from the National Zoo, was released from Children's Hospital yesterday.

The youth, who initially had been listed in critical condition and was treated with antivenin serum rushed here from around the nation, was described yesterday by a hospital spokesman as in good condition.

The spokesman said that "in the best interests of the patient" additional information about Morton would not be released.

Medical literature has listed only 10 previous cases of Gaboon viper bites, most in southern Africa, which is the snake's natural habitat.

No charges have been placed in connection with the theft of the vipers, whose venom is capable of killing an untreated victim within minutes. Officials of the Zoo Police, the law enforcement agency with primary jurisdiction at the zoo, said the incident is still being investigated.

They said they hoped to interview the youth and other persons who came in contact with him on the night he was bitten.

A reporter who went to the Morton family's basement apartment at 1307 Savannah St. SE yesterday evening could not locate the youth. Neighbors said they believed the boy's mother had removed most of the family's belongings from the apartment on Wednesday.

Morton was bitten shortly before midnight on the night of April 4 while carrying the two thick-bodied 4 1/2-foot-long snakes in a plastic trash bag slung over his shoulder as he left a Metrobus at 15th and K streets NW.

The bus driver said Morton had been carrying the bag when he boarded the bus about 11:15 p.m. near the zoo. Morton reportedly told a police officer he found the snakes in the bag in Rock Creek Park.

After the incident, fears were expressed for the welfare of the snakes by zoo officials, who described the vipers as passive creatures, unaccustomed even to slight disruption in their environment. The events of April 4, a zoo snake expert said, represented "the most activity these snakes will ever experience."

Yesterday, however, Dr. Dale Marcellini, the zoo's curator of herpetology said the animals were "doing fine." One of the pair, believed to be the male, is now again on display in the reptile house, Marcellini said. The other is still in seclusion in basement quarters, he said.

Whether the vipers' new-found notoriety has boosted attendance at the reptile house is difficult to determine, Marcellini said, noting that the house is perennially popular. But, he said, he has overheard comments about the biting incident that suggest some people are coming particularly to see the Gaboon vipers.