PROTOPLASM, the physical basis of life—to use A Huxley's oft-quoted aphorism—is the very stuff of life, but its mystery lies not merely in its composition but even more in its organization. The correlation between the structure and behaviour of the nucleus and the demonstrable facts of heredity is one of the outstanding achievements of modern science. Possibly for this reason the study of the cytology of the cytoplasm has suffered in comparison with the cytology of the nucleus. Particular interest is attached, therefore, to this book by Prof. Alexandre Guilliermond, professor of botany in the Sorbonne. The Cytoplasm of the Plant Cell By Prof. Alexandre Guilliermond. Authorised translation from the unpublished French manuscript by Dr. Lenette Rogers Atkinson. (A new Series of Plant Science Books, Vol. 6.) Pp. x + 247. (Waltham, Mass.: Chronica Botanica Co.; London: Williams Dawson and Sons, Ltd., 1941.) 4.75 dollars.