AT last we have the pleasure of welcoming the largest work so far written by one who is perhaps the greatest living master of experimental morphology. It has received admirable treatment by the Yale University Press; the clear printing aids the reader's eye, and the matt paper does justice to every nerve-cell in the numerous illustrations. Embryonic Development and Induction By Prof. Hans Spemann. (Yale University: Mrs. Hepsa Ely Silliman Memorial Lectures.) Pp. xii + 401. (New Haven: Yale University Press; London: Oxford University Press, 1938.) 22s. 6d. net.