For all practical purposes, pure recreational THC does not exist. You can't buy it, you can't snake it, you can't cat it, you can't smoke it, and no one's quite sure what it would do to you if you could.

This is one drug that has not made it from the pharmaceutical companies to the underground labs to the street. It is still: under the researcher's lock and key, and, so far, there have been very few security leaks. That doesn't mean no one has heard of it. On the contrary, many "knowledgeable" drug users swear they have bought guaranteed, genuine THC at one time or another, but then they probably also believe in Tinker Bell:

THC is the primary active ingredient `in every cannabis preparation, from marijuana to hashish to hash oil. Its -. chemical name, delta-9-tetrahydrocannabinol, defines its status as one of the chemical substances called cannabinols found in the hemp plant. These cannabinols share a similar chemical structure, but thus far only THC has been isolated as the mind-flexing, high-producing agent that makes the Can. nabis sativa plant unique.

THC was first synthesized in 1966. The extremely delicate and costly equipment needed to manufacture it has left THC solely in the hands of professional laboratories under regulated, contract to a limited number of bona-fide drug researchers.

These researchers only dispense pure THC for their marijuana' experiments. In synthesized form, THC dosage and quality can be carefully controlled.

Though this may be a boon to much-needed scientific research, it leaves the street user high and dry amid rumors of THC's miraculous qualities. Since it is the substance that produces marijuana's effect, the offer of a "pure" dose is understandably appealing to cannabis devotees. Unfortunately, Aim tunes out of ten, the unsuspecting consumer will buy a dose of the more dangerous drug PCP, and the other, time a combination of whatever leftovers his dealer can scrape together: LSD, mescaline, or occasionally amphetamines.

An average marijuana joint has about 1 percent THC content, while hash oil, at the other end of the scale, may have as much as 30 percent THC. PCP has no THC content, but has some other properties that aren't nearly so harmless (see PCP). To give you an idea of its danger, it is only legally available as n animal tranquilizer, since its use by humans was banned years ago for having created too many unpredictable side effects, such as convulsion and death. PCP is an extremely tricky drug to use,. even once, since a low dose may send you on a scary, totally confused, mental mystery tour, with numb limbs and sweaty palms. A high dose can lead to coma. The tricky part is that you can't predict your date, since the stuff is usually in a capsule or tablet of indeterminable mixture and quantity.

Real THE is a clear resin or sometimes a translucent, buff-colored goo. It has also been produced as a soluble white powder to be mixed with water. However, it is unlikely that you have ever seen THC, unless you've been in the deep freeze all winter along with the ice cream. THC is such an unstable subsance that it must be kept below freezing, in sealed glass vials, to retain its potency.

The drug causes the same effects as marijuana and hashish: up to three hours of a dreamy, euphoric state with intensified perceptions, a bit of confusion, and short-term memory loss. Occasionally the user may mildly hallucinate. THC causes an increased heart rate, reddening of the eyes, and a dry mouth resulting from reduced saliva flow. It is not physically addictive, nor-do regular users develop a tolerance. Overdose potential has not yet been determined.

At $1,000 an ounce, or about $15 to- $30 dose, it is not likely that the-pothead can afford THC, anyway. Besides, chances of scoring the real McCoy are somewhat akin to winning the Irish Sweepstakes, and when you lose, the PCP bummer you risk hardly makes it worth the gamble.