As studies in what we learn -- and don't learn -- about this hard world in the age of television, it would be hard to improve on the recent life-and- death spectaculars.

For 17 days, we hovered every evening at the cradle of "Baby Fae," as the baboon heart sustained her. Just as she passed on, our gaze could be shifted to the Humana Institute in Louisville, where we are now to keep vigil (as for Dr. Barney Clark before) over the second recipient of the Jarvis mechanical heart.

At the same time, in a darker drama half a globe away, we could watch the planes desperately ferrying food to the dusty, dying people in Ethiopia.

It has been quite a battle. But what, if anything, are these various scenes supposed to tell us about our prospects? Certainly that the reverence for life on however meager terms continues to engage us, and does us some credit.

But what the two sorts of scenes said about the problem of life was very different. In the sterile, orderly hospital corridors where the machinery of medical technology hums away, one might almost gather that life is in short supply, if more of it is wanted even on "artificial" terms. The impression in windswept, desolate Ethiopia was very much to the contrary. There seemed too much life there already, for the meager resources at hand.

But what linked both scenes was a shared indulgence in a sort of modern sentimentality, tending to misrepresent the issues of the abundance or quality of life.

The garish publicity swirling about the heart-transplant front -- which, at least in Louisville, would not disgrace the publicity apparatus of General Motors -- implies that there is a healthy future in machinery and plastics. In fact it is improbable that these expensive devices will alter actuarial trends in the least.

Those trends seem to be improving -- but they are improving because people living in industrial societies are learning more about the hazards of the overfed, underexercised life and are taking better preventive care of their circulatory systems. It's hard to knock "medical miracles" such as the mechanical heart. But what we are not very clearly told about William Schroeder is what kind of care he took of his first heart for the first 52 years.

As for the starving scenes in Ethiopia, which rightly arouse the world's sympathy, shock and pity, they also invite a misleading conclusion: that these poor people are victims of some terrible maldistribution of the world's resources.

That is possible, but in general the inference is quite wrong. Their desperation is rooted in local problems more avoidable than avoided, having less to do with distributive injustice than -- for example -- bad land management.

What Ethiopia is doing or not doing about birthrates, the protection of forests and fields (which are catastrophically shrinking, almost by the week) or farming methods is a better guide to its dilemma. Its plight, alas, foreshadows what will happen to more and more peoples living in comparable states of ignorance and privation. The damage they do to themselves, once done, is not easily undone, even if temporarily relieved by the world's charity.

Wherever we find victims, whether of fatty diets and immobility in the industrial world, or of starvation in the other, they stand for a related need to live on more knowing terms with fixed conditions.

Even with the technical counsel and aid that poor countries have a right to expect from fortunate neighbors, there's no predicting what political passions will render it pointless. To reach a threshold of self-sustenance is not the whole fight. Consider the Soviet Union, still struggling to induce its fields to grow wheat according to Marx, the city-bred bookworm.

Stripped of many layers of sentimentality and high emotion, these big news events of recent weeks may be distractions.

The late Rene Dubos, who was kind but not sentimental, said that as man defeats his older natural enemies -- including disease -- he will continue to develop new ones to take their place. This has so far been true. By the time we get to the miracles and tragedies, the real story to be told is often the preventable damage already done.