There was a time when ringer scandals only existed as distant memories of horse racing's seamy past. The Practice of running a superior horse under the name of an inferior one had been eliminated by a sophisticated system of safeguards.

The Thoroughbred Racing Protective Bureau boasted that since its inception in 1946 there had not been a single ringer case in America. But after a quarter-century without any such scandal, the sport has been beset by an epidemic of them.

In the last few months, 15 different ringer cases have been uncovered at tracks across the country. In Maryland there have been additional instances where thoroughbreds' identities have been mistaken. What has happened to the safeguards of which the racing industry was once so proud?

The need for a reliable system of identifying horses was made evident in the 1930s, when a legendary conniver named Paddy Barrie executed audacious betting coups on ringers. Barrie was an artist, and as a journalist of the era commented, he must have been a member of the postimpressionist school. He sent horses to the post under the impression they were somebody else.

Once Barrie's deft hand transformed a light chestnut colt named Akhnahton into a dark chestnut named Shem, and when his horse won at Havre de Grace by six lengths at 52 to 1, Barrie and his henchmen made a killing of $250,000.

To stop such outrages, the sport adopted a system of tattooing the lip of every thoroughbred with the registration number that appears on his foal certificate. Identifiers at every track would check the tattoo of every horse before he raced. Undoubtedly there were sharpies who attempted to alter the lip tattoo, but if anyone found a way to do it, no such case ever came to light.

It was in the early 1970s (TRPB officials believe) that a New England trainer conceived a way to beat the system. "I have to give him credit," said Paul W. Berube, the TRPB's secretary-treasurer. "It was a pretty good scheme."

Instead of altering the lip tattoo, the New Englander would forge the foal certificate. When the track identifier checked the number on the lip tattoo against the number of the foal certificate they would match-but it wouldn't be the horse he thought.

"The counterfeiters were able to obtain the same type paper stock that the Jockey Club printed its foal certificates on," Berube said. "Then all they had to do was find a bad horse and a good horse of the same age, sex and color. Beyond that the horses didn't evven have to look alike."

This simple, effective form of larceny triggered an outbreak of ringer scandals in the early 1970s, and forced racing authorities to come up with a remedy. It was simple. The Jockey Club began publishing an annual supplement to its Stud Book listing the rgegistration number of every thoroughbred foaled that year. The track identifier could check the umber on the foal certificate with the umber in the book and thus discover any forged certificates.

There was only one drawback. Many track identifiers weren't bothering to use th Jockey Club listings. "Checking the foal certificate numbers against the list of 20,000 registered foals was a time-consuming, tedious job," Berube said. "And some smaller tracks didn't even bother to buy the Jockey Club books."

As a result, larcenous horsemen could revive the same system of forging foal certificates that had worked earlier in the decade. They did-and it worked again, triggering the succession of ringer-scandal stories that appeared in the nation's newspapers throughout the fall and winter.

"If the track identifiers had checked properly, we would not have this outcropping of cases," Berube said. "But in each of the instances, they were not checking.

"What we have to do to stop ringers is to publicize the problem enough and instruct our agents at the tracks to monitor the performance of the identifiers. And we've got to make it easier for the identifiers to check each foal certificate against the Jockey Club records."

And then they've got to worry that no new sharpie comes up with a completely new way to beat the system.