ALITTLE OVER a year ago, a federal court in Washington, D.C. raised a few eyebrows when it acquitted a man who admitted to having possessed a quantity of marijuana. For years the court had quietly listened to sad stories of how defendants had been wronged by the marijuana laws, and for years the judges had summarily whisked the whining wrongdoers off to penitentiaries. But this case was different. In this instance the defendant was released because he truly did have a special reason for smoking the forbidden weed--he needed it to treat his worsening case of glaucoma.

Since that day, evidence pointing to marijuana's medical usefulness has mounted steadily, but federal laws continue to be based on the hysterical misinformation of the past. As was the case a year ago, patients cannot legally obtain prescriptions for medical uses of cannabis because federal laws classify the drug in the same group as heroin and other hard drugs.

The drugs in this group, the law says, lack accepted medical uses and are associated with a high potential for abuse.

So panic from the days of "Reefer Madness" lives on. It is now almost universally agreed that, when earlier laws were passed, research exonerating cannabis from its alleged harmful effects was repressed. It is also agreed that research at the time that linked the drug to a variety of dangers was contrived and unreliable. Yet, out of a sort of cognitive dissonance at the federal level, legislators are reluctant to admit past mistakes. Despite growing evidence attesting to beneficial medical uses of cannabis, antique laws continue to deny patients this treatment.

Claims of marijuana's usefulness in a medical setting are not new. In the last century, doctors prescribed extracts from the hemp plant for a variety of disorders. In the 1851 edition of the U.S. Dispensatory the following hints appeared:

The complaints in which (extract of hemp) has been specifically recommended are neuralgia, gout, rheumatism, tetanus, hydrophobia, epidemic cholera, convulsions, chorea, hysteria, mental depression, delirium tremens, insanity, and uterine hemorrhage.

Many eminent British doctors found the substance of equal use. Dr. J. Russell Reynolds, Fellow of the Royal Society and Physician in Ordinary to Her Majesty's (Queen Victoria's) Household wrote in 1890 that he had prescribed cannabis for 30 years and considered it "one of the most valuable medicines we possess." (Did the otherwise straitlaced Queen, a joint dangling from her stiff upper lip, know something we don't know?)

It was not until the 1920s and 1930s that this country, under intense pressure from the newly-created Federal Bureau of Narcotics--an agency in search of a mission--witnessed the crusade to banish the killer weed from American society, a society in which recreational use of marijuana was steadily becoming more popular. Contemporary newspapers frequently ran articles of purported instances where one marijuana cigarette had led previously respectable citizens to commit crimes of violence or had sent them into fits of insanity. The stories, of course, were told in lurid detail and did much to boost sales. These imaginative stories, combined with the mistaken belief that the drug was highly addictive, led to a series of laws which, while not banning medical uses outright, imposed severe taxes on such uses. As a result, prescription of the drug fell to insignificance.

So in 1970, when the Controlled Substances Act was up for consideration, there was little recent evidence on which claims of the medical usefulness of marijuana could be made--both research and prescription had been inhibited by federal laws. Combined with a new onslaught of "scare" studies, this persuaded the Congress to list THC (the active ingredient in marijuana) as a "Schedule I" drug. This meant that, even under medical supervision, the drug was too dangerous to be used. As a sop to those who protested, Congress set up the National Commission on Marijuana and Drug Abuse to study the problem and make recommendations. Unfortunately, it seemed that members of Congress would only be interested in study results if the Commision told them what they wanted to hear. In its 1972 report, the Commission found that intermittent or experimental use of the drug was relatively safe, that marijuana did not pose a major health threat to the public, and that, while cannabis was not wholly innocuous, only chronic heavy users were at risk. The report, though, went unheeded, and THC remains a Schedule I drug.

While prescription of the drug is illegal, researchers can, under strict controls, use marijuana experimentally, and recent evidence has confirmed what doctors thought over a century ago--that marijuana holds great promise for medical use. It has been found that THC can cause up to a 40 per cent reduction in interocular pressure, a cause of glaucoma and blindness. It is more effective than most drugs currently used for this purpose, and avoids the serious side effects that accompany use of conventional drugs.

Yet marijuana's medicinal uses are not limited to glaucoma. One of the most promising uses of the weed is the role it can play in soothing the often-severe side effects of chemotherapy for cancer patients. These side effects--vomiting, nausea, and loss of appetite--are sometimes so unbearable as to drive patients to less effective methods of treatment. Marijuana is very effective in controlling vomiting and nausea and in stimulating appetite, and it is thought that if doctors were allowed to prescribe the drug, it would be far more reliable than drugs currently available.

THC may also be useful in the treatment of asthma; inhalation of the drug dilates bronchial passages in the lungs. One problem with this treatment is that the smoke from marijuana cigarettes sometimes disturbs delicate lung tissue. For this reason, doctors are now considering the desirability of administering THC in aerosol form to asthma patients. Other uses have been recently suggested, though they require further study. Cannabis is an anti-convulsant which may be useful in treating epileptic attacks. It may be able to replace more dangerous drugs, such as barbiturates, in the treatment of insomnia. The drug's analgesic, preanesthetic, and antidepressant qualities show promise for treating alcoholics and in mitigating the effects of heroin withdrawal. Marijuana may be useful for relieving hangovers, and experimentally, direct application of THC has even caused an 82 per cent reduction in tumors in mice.

Yet, while science advances, patients are denied what may be an effective treatment for many human ills by the persistence of antediluvian notions of the drug's ill effects and of archaic legislation. Those who oppose allowing use of marijuana as a prescription drug point to numerous studies that have accused it of horrible side effects ranging from lowering hormone levels in males to damaging brain tissue. Many of these studies, though, are methodologically dubious; the political requirements of funding never take precedence over sound research technique. Generally, these studies use extremely high dosage levels to establish harmful effects. Few establish close matches between the control and test groups, and when abnormalities are found in the test group, it is not uncommon to find that the group's members, unlike those in the control group, had previously used other more powerful drugs. These experiments are seldom replicated. Moreover, several recent studies have found no deleterious effects in humans who have used potent forms of the drug (such as Jamaican ganja) for long periods of time. It has also been charged that the government drug bureaucracy has tried to repress reports that have found marijuana to be benign.

But even if there are legitimate grounds for doubting marijuana's safety, most experts agree that only chronic, heavy users are at risk. No one has suggested that occasional use is harmful, and even in forms of medical treatment which require long-term ingestion of cannabis, it should be up to the doctor to decide if the risks of the drug exceed its benefits. Especially in the case of cancer patients, marijuana may be the only way that acceptable treatment can be endured, and therefore any risks which marijuana may carry with it should be acceptable. Even HEW, in their 1975 report, concluded: "Like everything else (marijuana) should be used for its beneficial effects and avoided for its noxious aspects."

Besides, the main reason for even bothering to pass the Controlled Substances Act in the first place was to keep drugs out of the hand of those who might abuse them. This goal has obviously not been met: over twenty million Americans have tried marijuana, and thirteen million use it regularly. It is not likely that legalizing marijuana as a prescription drug would result in any significant increase in use among non-patients; those who want it now do not have much trouble obtaining it.

Even those who take the position that there is some legitimate purpose served by making criminals out of those who smoke marijuana should admit that the law has gone too far for too long, and that restrictions should be relaxed to allow marijuana to be prescribed when doctors feel that the symptoms call for it. Some day marijuana may reduce the suffering of many patients and even save the lives of others. This will not require a new medical breakthrough, but only a modest effort to overcome the vestiges of paranoia from another age.