Taking her third annual stab at summer stock, Miss Ann Corio is currently murdering another play in cold blood at the Cambridge Summer Theatre. Undeterred by the critics' chilly reception of her two former expeditions to the hustings, Ann has gone steadily on in her campaign to make herself the new Duse of the American theatre.

Her latest effort, "It's a Wise Child," is an innocuous, frothy story, in which the actors, and even the audience, seem to have a good time. Its leitmotif is the tribulation of two young unmarried ladies who are about to have children (one for Corio, and one for a mysterious creature named Annie, who never does appear.) Variations on the theme, which continually keep running in and out, include the struggle of a bouncing young man, played by Charles Bell, to get ahead in the world, the quarrels between a character evidently inspired by Caspar Milquetoast, played by Robert E. Perry, who also found time to direct the play, and his wife, played by a peroxidized young lady named Louise Kanasireff.

Mr. Perry, it is quite obvious, spent too much time learning his lines to direct the play adequately, for its continuity is poor and it lacks even the subtlety that this garden variety of bedroom comedy commonly aspires to.

Two of the all-too-few bright spots are supplied by Mary Barthelemess, in the part of the maid, and William Mendrek, whose role is that of an iceman. Although overdone, their characterizations ring true and furnish many laughs. Allan Tower, who plays the part of the Big Bad Businessman, has the curious aura of "Ten Nights in a Barroom" about him and the end of the play finds you surprised that he has produced neither a long black mustache, or whip.

Perhaps the biggest paradox of the entire production is the fact that the finest acting is done by a Yale man. Edmon Ryan, in the part of the lawyer who eventually solves everyone's problems, plays his role with a sureness that is quite refreshing and which stands out more than do Miss Corio's obvious charms.

"It's a Wise Child," written by Laurence E. Johnson, represents the beginning of what "Variety" calls "summer fare." It is a good bet if you're looking for something relaxing after finals, but if you're looking for something more, either from Miss Corio or from the play, you will be disappointed.