THE SUBJECT -- the patentability of living things -- probably merited the headlines that Monday's Supreme Court decision received, but the decision itself did not. For the philosophical implications are enormous -- as, incidentally, are the a mounts of money likely to be involved. But actually the Supreme Court's ruling turned on a narrow legal question and will change little.

The patent law, essentially unchanged since Thomas Jefferson drafted it to encourage invention and technological progress, states that "whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter . . . may obtain a patent therefor." Twice, in 1930 and again in 1970, Congress passed special laws granting patent protection for new types of plants.The narrow question the Supreme Court had to decide was whether the basic patent provision was intended to cover living things or whether Congress' later action on behalf of plants should be taken to mean that until Congress says otherwise, only plants among the living universe are patentable.

As the 5-4 vote implies, the decision could have gone either way. No grand principle was involved -- simply an interpretation of inference of congressional intent. The majority view held that the essential distinction in the plant laws and the patent law itself is "not between living and inanimate things, but between products of nature, whether living or not, and human-made inventions." The genetically engineered oil-eating bacterium that was at issue in this case was clearly, the majority felt, "not nature's handiwork" but man's, and therefore patentable.

Nor was this the first time that a patent had been granted to cover a bacterium or other living thing. The first of many such patents was granted to Louis Pasteur in 1973. Why, then, all the excitement?

The answer is that his decision comes at the beginning of what is likely to be -- without exaggeration -- a new industrial revolution. Recent discoveries in molecular biology, especially the techniques of recombinant DNA, have opened up the possibility of producing substances of tremendous medical, industrial and human value in genetically engineered micro-organisms. The potential markets seem boundless, and Wall Street's enthusiasm for biotechnology is growing by leaps.

It is this enthusiasm, lured on by the promise of enormous profits, and now presumably further encouraged by the granting of patent protection, that critics of the Supreme Court decision fear. Too rapid commercial application of the new techniques could easily lead to tragic mistakes. But regulation of that development is, the court unanimously agreed, a matter for Congress to decide -- just as it may also decide to amend the patent law specifically to exclude certain types of living things.

So far, recombinant DNA work has been regulated by the National Institutes of Health with the advice of an advisory committee of experts in science, law, education and government. Initiated by the scientists who made the early breakthroughs in recombinant DNA techniques, it has been a uniquely successful model of responsible self-regulation. The real question that the court's decision poses for Congress is whether the NIH procedure -- which is still mostly geared to regulating laboratory research -- is adequate to regulate the explosive burst of commerical involvement in biotechnologies that is clearly about to happen.