To people with short memories, the ruling made by the Maryland Racing Commission Thursday might seem undramatic and boringly technical. Horses may now be treated with the drug Lasix if an examination with a device called an endoscope reveals that they bleed internally after exertion.

But the decision to allow the relatively wide-open use of the antibleeding medication evokes the bad old days when Lasix was first being used in the state. In my whole life as a horseplayer, I never experienced a more depressing, maddening, frustrating time, and I am afraid history may be about to repeat itself in the next few months.

In 1973, when some Maryland trainers started to treat their horses with Lasix, racing fans didn't know exactly who was getting what, but we knew that something crazy was happening. One day a horse would tire and lose a sprint by a dozen lengths; a week later, he would win at a route and be widening his margin at the finish. Certain trainers with clout were able to get "bleeder slips" for just about all of their horses, and when they claimed an animal from a trainer who didn't have such easy access to Lasix, they might improve him by 10 or 20 lengths overnight.

The very essence of the sport was being undermined. Playing the horses is the greatest game in the world because it is rational and logical; a handicapper can reasonably hope to make money if he is smart enough. But now a new, incalculable element was being introduced into the game, and only trainers and vets could hope to understand it.

But the racing industry showed no concern for the interests of its customers, the bettors; instead, they treated us with infuriating condescension. At the 1974 hearing that finally legalized completely unrestricted use of the drug, a prominent veterinarian assured the racing commission: "I guarantee that Lasix won't make a horse that runs six furlongs in 1:11 1/5 go in 1:11." The chairman of the commission assured the public: "This material doesn't change a horse's form one iota; it just prevents him from bleeding."

Ha!

Widespread public opposition eventually prompted the racing commissions in Maryland and most other states to curtail or abolish the use of medications on racehorses. So it seems a little hard to believe that, after the passage of so little time, horsemen and their lawyers are offering the same bogus assurances and the same old arguments in favor of the drug.

This time, of course, there is one new twist. Modern technology has shown that the old definition of a bleeder--a horse who bleeds visibly through the nostrils--is inadequate. Endoscopic examinations reveal that many horses have the same type of problem but don't show it because they bleed internally. When the owners of Desert Wine went to court to get permission to treat their colt with Lasix in the Preakness, Judge Robert Hammerman concluded that it was "arbitrary" to define bleeding only as the visible kind.

Hammerman's ruling forced the commission to modify its own rules, as it waits for the National Association of State Racing Commissioners to issue a set of guidelines for Lasix use. But in the meantime, use of the drug is probably going to be wide open.

Approximately 50 percent of all horses do show some signs of internal bleeding under endoscopic examination. Moreover, the commission will allow private vets--not just the state vet--to conduct these examinations. These are some of the the same vets who, a decade ago, were throwing around bleeder slips like they were confetti.

What's the alternative? The case of Desert Wine--the horse largely responsible for this whole mess--may be instructive. Just last week, the colt's owners were arguing vociferously that it would be dangerous and unfair to make him run in the Preakness without Lasix. But Desert Wine will make his next start in the $150,000 Ohio Derby on June 19, in a state which does not permit use of the drug. Trainer Jerry Fanning explained that if he made certain changes in Desert Wine's diet and regimen and gave him sufficient rest that he could run without Lasix and without a real risk of bleeding.

Of course, some trainers think it would be terribly unfair if they had to give their horses rest and proper care every time they needed it instead of taking the convenient shortcut and giving them drugs. Unfortunately, not only the horses but also the public has to pay the price for the trainers' addiction to Lasix.