As I write, Baby Fae is no longer "critical." The same cannot be said for the hosts of antivivisectionists, animal-rights advocates and anti-experimentalists who think that the operation that gave Baby Fae a chance to live was a medical travesty.

Some are critical that the doctors at Loma Linda University Medical Center didn't try very hard to find a human heart with which to replace the 18-day-old infant's defective one. Some are critical that the transplant was unnecessarily experimental. And some are critical that it entailed the deliberate killing of the baboon.

That last group of critics is the hardest to understand. It seems reasonable, as a general proposition, to prefer more conservative medical procedures to radical ones, though it stretches language to call even human-to- human organ transplants conservative. Still, before Baby Fae, no human recipient of an animal heart had lived longer than the 31/2 days managed by a South African who was given a chimpanzee's heart back in 1977.

Those critics (including some well-known heart surgeons) who accuse the California doctors of being more interested in advancing medical science than in saving Baby Fae's life make a reasonable case -- particularly in light of the fact that a human heart was available 70 miles away on the day of the surgery. (The surgeons say the human heart was too large and, anyway, time was running out. But a hospital spokesman acknowledged that they wouldn't have used the human heart anyway, since animal transplants are "our area of expertise.")

But what of the critics who contend that it was wrong to take the life of the baboon, even to save the life of a human infant? Theirs is the argument that eludes me. I've talked to them, and I've read their books on "animal rights," and still they leave me behind.

Talk to me about the savagery of bashing baby seals, and you've got a willing audience. Tell me it's wrong to kill animals for sport, or for fur coats, and at least I can understand your point of view.

I can even understand (though I don't agree with) those critics who say it is wrong to inflict suffering on laboratory animals in order to learn how to ease human suffering. But tell me that Eskimos should become vegetarians rather than take the life of a whale, or that it is wrong to sacrifice a baboon to save a human life, or even to learn to save a human life, and you lose me completely.

Those who stress the sanctity of all life tell me that my attitude is nothing more than an extension of the ethnocentricism that leads some people to conclude that it is all right to sacrifice Jews for the benefit of Aryans, or aborigines for the good of "civilized" humanity, or blacks in the interest of whites. Life is life, they insist, and mine is no more sacred in the eyes of the Creator than that of a field mouse. I think they're mistaken, but I have learned to be more careful in the way I say it.

I once made the mistake of criticizing the animal-rights advocates for showing more concern for animals than for fellow humans, and I got zapped by a number of irate readers who reminded me that I had no way of knowing the level of their concern for human beings. Fair enough.

But when it comes down to a clear choice of sacrificing an animal to save a human -- as it well might as a result of the Baby Fae experiment -- the choice seems ridiculously easy. Maybe it's nothing more than my pro-human prejudice, but I don't see what all the fuss is about.