``A dairy cow. A city boy. A silver pail. A wooden stool''- -everything but the expertise. Result? ``No milk''--not in response to a pat or a kiss, food or a joke, entertaining tricks or anger. At last, the placid cow grows impatient with the boy's obtuseness; and when she stands over the pail, the boy realizes what he should do. The circumstances are so implausible that they may amuse knowledgeable children--and even some city kids--with their exaggeration, but the story is most effective as a parable. The futility of inappropriate efforts makes an obvious subtext to the succinct quatrains; children will also enjoy chiming in with the reiterated ``But no milk!'' Making her first US appearance, Eitan--an Israeli who has been nominated for the Andersen Award- -provides freely rendered illustrations in pastel and gouache, with bold designs, vibrantly expressive figures, and brilliant colors accented with dramatic black (especially the formally dressed little boy's suit). A fine debut for Ericsson, who's especially fortunate in her illustrator. (Picture book. 3-8)