Failure of the University of Michigan to state the charges against a group of students dismissed last June or to grant the students the open hearing they have repeatedly requested was sharply condemned in a letter sent to President Alexander G. Ruthven yesterday by 250 educators, churchmen and writers.

Dean Ned H. Dearborn of New York University announced that the 250 signatories were distributed among 52 American universities and colleges, and included several outstanding alumni of the University of Michigan.

Heading the list were the Committee's honorary chairman, Professor Frans Boas, and Professor Wesley C. Mitchell, both former presidents of the American Association for the Advancement of Sciences; Oswald Garrison Villard, former publisher and editor of "The Nation"; Dr. Carleton Washburne, president of the Progressive Education Association; Professor Ralph Barton Perry of Harvard University, author of the Pulitzer Prize biography of William James.

Also Dr. John P. Peters of the Yale Medical School, secretary of the Committee of Physicians for the Improvement of Medical Care; Professor Morris R. Cohen, former president of the American Philosophical Association; Dr. Harry F. Ward of Union Theological Seminary, former president of the American Civil Liberties Union; and Sterling A. Brown, outstanding Negro poet.

The letter noted that, as "chief executive officer of an institution established to educate young men and women for intelligent citizenship in a democracy," a university president has the responsibility of creating "a university atmosphere in which democratic procedures and attitudes prevail."

"We cannot reconcile," it continued, "the treatment of dismissed students with such a conception of the university, and especially of a state university. Dismissal without charges, unsupported allegations of being a 'disturbing influence,' denial of an open hearing--these are not the methods by which a democratic society can long continue to exist."

Continued refusal by University authorities to grant an open hearing, the letter concluded, "will inevitably lead many to the conclusion that the University of Michigan can no longer be classed among the truly free institutions of higher learning."