RECONSTITUTION OF COMPLETE ORGANS FROM SINGLE-CELL SUSPENSIONS OF CHICK EMBRYOS IN ADVANCED STAGES OF DIFFERENTIATION.

Summary.-Single-cell suspensions prepared from kidney, liver, or skin of 8-to-14-daychickembryos, scrambled, recompacted, transplantedtothe chorio-allantoic membraneof 8-day embryos, andexamined9 dayslater, proved to havebeen able to give rise to remarkably complete and morphologically well organized organs ofthe respective kinds, with the various tissue components in their normal mutualrelations and functional activity. The results re-emphasize internal "self-organi-zation" as one of the mostbasic problems in the study of development, in contra- distinction to contemporary preoccupation with external "inductions." * These investigations weresupportedin partbygrants fromthe AmericanCancerSociety andthe National Cancer Institute (National Institutes of Health of the Public Health Service), and significantly aided by the competent technical assistance of Mr. Albert Bock.1 Weiss, P., Abhandl. z. theoret. Biol. H., 23, (1926). 2 Weiss, P., Principles ofDevelopment (New