"The present prosperity of the country is soundly grounded," despite some inflation and a high rate of spending, Sumner H. Slichter, Lamont University Professor, declared yesterday.

In an article in The New York Times Magazine, Slichter said that the most "realistic" view of the American economy is held by the "optimistic skeptics," who feel that the gradual rise in price levels is "largely determined by influences over which men have only very incomplete control."

Today's enormous consumption of raw materials will lead to shortages and high prices of metals and oil, and easy credit terms and technological developments creating greatly increased demands for consumer goods, he said.

He concluded that although these trends indicate that prices will continue to rise, "this slow, creeping kind of inflation is not the kind that ends in collapse and severe depression."