Thirty-odd years ago, another time when legislative scandal was troubling the country, a one-term congressman from Indiana, Andrew Jacobs Sr., spoke with pith and acuity.

"You can't dip clear water from a muddy stream," Jacobs said.

This week, that old truth was revived. Two days ago, Rep. Robert E. Bauman (R-Md.), the conservative exemplar, told the world that he had a drinking problem. That confession was prompted by the revelation that he had agreed to undergo rehabilitation rather than face trial on a charge of soliciting sex with a teen-age boy.

On the same Black Thursday of the 96th Congress, Rep. Michael (Ozzie) Myers (D.-Pa.) told House colleagues about to expel him for taking bribes in the FBI's Abscam "sting" case that he, too, had a drinking problem.

"I was drinking FBI bourbon, big glasses of it. And I'm a beer drinker," the erstwhile dockhand from Philadelphia explained to the House.

Only days before, Rep. John W. Jenrette Jr. (D-S.C.), another of the Abscam bribery defendants, was saying in federal court that devlish alcohol had driven him to uncongressman-like conduct.

And that is only the scorecard for the past month. The 96th Congress, perhaps more than any other in recent memory, has been shaken by one tawdry revelation after another.

Bauman is but one of several congressmen who have publicly acknowledged homosexual relationships or activities in recent years.

Several other -- Sen. Herman E. Talmadge (D-Ga.), and Reps. Joe Wyatt Jr. (D-Tex.) and Richard Bolling (D-Mo.) -- have made public confessions of their inability to cope with alcohol, admitting to taking the "cure."

In the House, Charles C. Diggs Jr. (D-Mich.) began a prison sentence in July for mail fraud and payroll cheating. Daniel J. Flood (D-Pa.) resigned in January before pleading guilty to conspiracy charges. Talmadge was "denounced" by the Senate over charges that he cheated on expenses and converted campaign money to personal use. The list continues . . .

The temptation, of course, is to conclude that the institution is going to hell in a handbasket, cluttered with drunks, perverts and suborners -- the precise opposites of what the voting public expects in its servants.

Well, it may or may not be infernally cursed. It may more probably be nothing less than what it always has been, a reasonably accurate cross-section of the public it is elected to represent.

Two hundred years ago, George Washington was saying as much when he described Congress, in his eloquent post-Colonial manner, as representing and reflecting the heart and soul of the nation.

If one accepts the cross-section theory, it may follow that at least 7 percent of the 539 members of Congress have serious difficulties with alcohol, or that 10 percent are homosexual, both percentages frequently cited benchmarks for American society as a whole.

"There is no question," said Norman J. Ornstein, a political science professor at Catholic University, "that Congress has always reflected the public in its foibles."

But, Ornstein continued, "I believe that years ago, from the 19th century up until about World War Ii, there were more shady characters in Congress than now. There were more with those visible weaknesses -- alcoholism, sexual activity, bribery. They just didn't get reported."

Attitudes were different, too. For example, Daniel Webster, the 19th century senator, is remembered more for his oratory that for his retainer from the banking industry -- a financial arrangement that today would likely earn him scorn and derision.

Clearly, what differs in 1980 from the America of George Washington and Andrew Jacobs Sr. is that alcoholism and homosexuality are out of the closet, scandal and moral questions are of wider public concern, and the press has shed a traditional reluctance to chronicle legislators' personal pecadilloes.

A press watershed may have been the fabled 1974 Tidal Basin episode of former congressman Wilbur Mills (D-Ark.), then chairman of the Ways and Means Committee, whose drinking and carrying on with strip-tease queen Fannie Foxe shocked the public.

Mills admitted to an alcohol problem and left office under a cloud. The press, stunned by its ignorance of Mill's personal habits, began paying closer attention to the private side of public lives.

A new study by Michael Robinson, another political scientist at Catholic University, compares news coverage of the bribery cases of former senator Danfiel Brewster (D-Md.) and Flood, similar but separated by about a decade.

Robinson found an explosion of news coverage of Flood's difficulties, which ended with his resignation in January and a guilty plea last February to conspiracy charges. Brewster, who also had a bout with alcoholism, got appreciable media attention, but markedly less.

"After the Tidal Basin incident, it became respectable to report events of that kind," Ornstein said. "If rumors about Bauman had circulated 10 years ago, most reporters would have been reluctant to report the story."

In some instances, public officials were more forthright about their problems than reporters. Sen. Harrison A. Williams Jr. (D-N.J.), under investigation in the Abscam case, one-upped the press in the early 1970s by publicly confessing what reporters knew but did not write -- that he had a serious drinking problem.

Reporters reacted with similar reticence, knowing that such respected figures as the late senator Lee Metcalf (D-Mont.), Sens. Russell B. Long (D-La.) and Warren G. Magnuson (D-Wash.) once found solace in a workaday bottle. Reporters used to refer joshingly to Long as "Jack Daniel."

In an institution under as much pressure as Congress, populated by an army of ambitious overachievers, the wonder may be that the yielding to temptation is not greater.

"Members of Congress are a select group," said an official of the National Institute of Alcohol and Drug Abuse. "We know that persons with high exposure are more prone to have alcohol problems. For politicians, liquor is available every time they turn around."

The congressional life style is ready-made for submission. Legislators spend great amounts of time away home and family; public adulation comes easy; pressures are intense -- reelections, responding to favor-seekers, warding off the bearers of gifts.

Yet even in an era of heightened public sensitivity toward the errant official, voters show a remarkable ability to forgive and forget, maybe even seeing a bit of their own frailty in Sen. X.

Talmadge, for all his troubles, survived a tough primary. Wilkes-barre made Dan Flood its "man of the year" when the roof was collapsing on him. Williams, his secret in the open, was easily reelected, Ditto Diggs.

A forgiving constituency returned Rep. Frederick W. Richmond (D-N.Y.) to Congress after he acknowledged involvement in an incident of homosexuality that led to a charge of soliciting sex for pay. Former representative Wayne Hays, who quit in 1976 after charges that he kept Elizabeth Ray on his House payroll as a mistress, got elected to the Ohio General Assembly and is talking of returing to Washington.

The Jacobs family of Indianapolis, still holding a seat in the House in the person of Andrew Jacobs Jr., had another way of putting these things.

Joyce Jacobs Sr. liked to say, "There's so much good in the worst of us, so much bad in the best of us." That is Congress and that is America.