In a way Karl Marx never may have intended, his Chinese disciples are attacking the soft life of the American bourgeoisic.

They're severely raising the price of downy pillows, cashmere sweathers and camel's-hair coats.

It is ayet unexplained turn of events that perhaps has affected Americans more immediately than have any of the other murky things that have been happening in China this past year. Hong Kong and U.S. clothing salesmen are complaining of a 20 to 30 per cent rise in the cost of high-quality camel's hair and cashmere, and feather-and-down trade experts say prices are up by an incredible 12 per cent - yet sales of Chinese down to cushion American heads and rumps still skyrocket.

As a result, the rumor mill among traders here about the mysterious doings of double-humped Mongolian camels, Central Asia mountain goats and Russian ducks has become at least as energetic as the better-publicized speculations over the fate or political leaders in Peking.

"I hear they're loaded with cashmere up in Inner Mongolia and just can't get it out," said one trader. "They're just keeping it all to produce their own sweaters," said another.

V. Woo of Robert's Tailor Shop here calculates that a camel's-hair sportscoat that sold for $140 last year is now up to at least $170 even in discount-conscious Hong Kong. His competitor across the shopping aisle of the fashionable Mandarin Hotel, Frank Shang of Royal Fashions, said the increases have discouraged his American customers."The tourists who come in in groups say they can't afford it," he said, though he adds that some wealthy European customers still place orders.

The Chinese appear to have provided the clearest explanation for the phenomenal rise in down and feather prices, according to American middlemen who have discussed the problem with them. "Worldwide demand has been accentuated to a great extent by failures in Eastern European agriculture," said one trade expert. The Chinese say many ducks were slaughtered when the Russian grain harvest dropped sharply in 1974, and efforts to accelerate growth of Eastern European ducks with special chemical feeds have cut the quality of their down.

This allgedly has produced the great demand for Chinese stuffing in American pillows. Down and feather exports to the United States are said to have increased fourfold. About half of that increase is the result of inflation.

Few reliable figures are available. Some China-trade watchers say the country is exporting half its usual volume of the cashmere and camel's hair; others say the exports have dropped off only slightly, probaly because of transportation and other problems arising from the year's political turmoil.

If anyone would be adversely affected by fiery political debate in the People's Republic, it would be what is called the "ammal byproduct" producers, who often fill the role of the hated capitalists of old. The men and women who comb the cashmere from the fleece of mountain goats, collect the shed camel's hair or pluck duck feather are taking time out from the collectivized food production that Peking insists be put first. In times of trouble these "sidelines" enterprises, and the personal profits they reap, are considered expendable.