It is not often that kind words are said of the U.S. House of Representatives, but let me voice a few kind words today. The House last week rose superbly in support of the Endangered Species Act of 1973. It may have been a bad day for those who trawl for shrimp in the Gulf of Mexico, but it was a great day for everyone else.

Not much ever is written about the act, and more's the pity because it ranks among the most farsighted pieces of legislation in this century. Indeed, about the only time the law gets into the news is when some dam builder or real estate developer howls about its application. Then we are importuned about the absurdity of saving the furbish lousewort or the black-capped vireo. What good is the checkerspot butterfly or the toadflax cress?

To these jeers and catcalls, environmentalists make a quiet response: for every living thing there is a purpose. We may not understand what that purpose is, but each generation has an obliga-tion to the next generation. We are conservators of a complex and priceless estate.

In times past Americans have been poor trustees. The passenger pigeon and the ivory-billed woodpecker are gone. But through the Endangered Species Act, we are trying to make amends. Nearly a thousand species of animals, fish, plants and crustaceans now are formally listed as either ''endangered'' or ''threatened,'' and these benefit from the full protection of the law. More than 250 recovery plans are in operation, as biologists seek to expand dwindling populations of the bald eagle, the peregrine falcon, the grizzly bear and other species. The effort has its setbacks; the giant condor may not survive. But it has successes, too; alligators are off the endangered list, and the first pairs of red wolves that had been raised in captivity have been released in the wilds of North Carolina.

On Dec. 17 the House took up three amendments that would have weakened administration of the act. The worst of these came from Rep. Wes Watkins of Oklahoma, who wanted Congress itself to ''de-list'' a tiny minnow known as the leopard darter. He made a good argument, citing research that indicates the species is thriving, but adoption of his amendment would have set a ruinous precedent. He lost by a vote of 273-136.

A more serious challenge came from Rep. Solomon Ortiz of Corpus Christi, Texas. By way of background: Five species of sea turtle are listed as endangered. Of these, the most in trouble is the Kemp's ridley. Forty years ago 40,000 females were nesting on a single day at the one beach in Mexico that is their home. Today the number is down to about 250.

The National Marine Fisheries Service estimates that as many as 4,000 turtles are killed every year in the Gulf of Mexico when they get entangled in the nets of shrimp trawlers. These casualties can be prevented by use of a turtle eluder device (TED) attached to the net. Pursuant to the act, shrimpers have been ordered to use the TEDs, and the shrimpers are furious. The Ortiz amendment would have suspended the regulation for two years.

Ortiz eloquently pleaded the cause of the 13,000 shrimp crews who would be put to the expense of TED installations. He challenged the government's research as inadequate; he estimated the economic loss to Texas alone at $400 million a year; he feared that 30 percent of a day's catch would be lost because of the TEDs; he cited the futility of conservation efforts by the United States when Mexico does nothing; and he had the support of such Gulf Coast Republicans as Trent Lott of Mississippi.

The House rejected the Ortiz amendment by a vote of 270 to 151, but authorized $1.5 million for further research on the devices. Led by Walter Jones of North Carolina, members refused to substitute their own acknowledged ignorance of sea turtles forthe presumed expertise of marine biologists.

A final amendment came from Ron Packard of California. In an emotional plea to the House, he proposed that administrators of the act be required to consider the impact of a species listing upon human beings. It is wrong, he argued, to block construction of a needed highway simply to preserve the habitat of five endangered birds. The House, unmoved, killed his amendment 266-151, and then passed the reauthorization bill by a walloping 399-16.

The bill will provide adequate funds for the next five years. Of equal importance, the final vote will assure the administrators of solid support on Capitol Hill. Hail the leopard darter! There's a minnow to stand by.