The battle of wits between trainers who use illegal drugs and chemists who try to detect them has been reging for decades. Now the trainers appear to be winning decisively.

The extent of the problem was suggested in my column Saturday describing the successful effort to find a test for the narcotic Sublimaze. Racing chemists across the country worked for a year trying to detect this drug. While they were doing it, countless new drugs presumably were being developed and introduced at the country's race tracks. They are going to be even more sophisticated.

Testing for Sublimaze may prove to be child's play compared with the type of drugs experts say are the wave of the future. Scientists describe them as "endogenous," meaning that they are substances naturally manufactured by the body. One relatively benign type of endogenous drug, steroids, has been used at race tracks for years, and chemists have found it practically impossible to differentiate between artificial steroids and natural ones.

New types of endogenous drugs may be far more potent. Scientists know that some individuals have a greater capacity to withstand pain than others, and they are learning that the reason is not simply psychological toughness. The body evidently manufactures substances that serve as a buffer against pain, and eventually they will be isolated, reproduced in a laboratory and introduced at race tracks. And the trainers will have an incredible new weapon.

"Drugs isolated from biological systems present tremendous problems," said John McDonald, director of the Illinois Racing Board's laboratory. "Detecting Sublimaze was difficult enough. That was like throwing a grain of salt into a 55-gallon drum, filling it with trash and garbage and then trying to retrieve the single grain.

"But with these new drugs, it's like throwing in the grain of salt, filling the can with cement, and then trying to identify the original grain of salt from all the salt which occurs naturally in the cement. It's the hardest type of analytical chemistry."

Difficult as it is, the fight against illegal drugs need not be a hopeless cause. The racing industry does have ways to deter their use.

One such method was employed in Illinois and led to the suspension of trainers for administering Sublimaze. Even when they did not have a test for the narcotic, officials in the state suspected strongly that it was being used. So they saved postrace urine samples over a period of weeks. When the test had finally been developed, they reanalyzed the samples and caught the offenders retroactively.

Only a few states save urine specimens after they have initially tested negative.Maryland is not among them. But the practice would deter a trainer from using an illegal drug evenif he knew his state's chemists did not yet have a way to test for it.

Another possible solution for drug abuse would be so effective that horsemen shriek wheneven it is suggested. Most narcotics have to be administered a very short time before a race. If all horses had to be in a detention barn under supervised quarantine for a few hours before they raced, the drug problem would disappear overnight.

Drugs used to be a blight on dog racing, but in the early 1960s tracks began the paractice of isolating dogs for several hours before they compected. The practice has turned dog racing into the most honest of the parimutuel sports -- far more honest than the Sport of Kings.