Phase-contrast radiography using an x-ray interferometer is presented for observing organic matter. High sensitivity of phase-contrast radiography is demonstrated with a rat cerebellar specimen without staining it with a contrast medium. The layer structure of the cerebellum can be observed in the obtained image while there is no clear structure in the corresponding absorption-contrast image. Quantitative image analysis is made possible by converting an x-ray interference pattern to an x-ray phase shift distribution. The lipid distribution in the cerebellum is discussed by evaluating x-ray phase shifts before and after lipid removal.