Dr. Marc J. Kahn (Medicine), professor and section chief of hematology, and his mentee from the University of California San Francisco recently published a chapter in the book, Blood Substitutes and Oxygen Biotherapeutics, published by Springer. Their chapter, titled, "The Erythrocruorins as Synthetic Blood Products: What Is New?," describes the potential role of the erythrocruorins, derived from the common earthworm, molluscs, and some insects. These compounds are cellular-free hemoglobins of large size that may serve as human blood substitutes due to their oxygen carrying capacity and lack of immunogenicity.