This work is a philosophic study, from a biologic standpoint, of the living substance. The work was carried on partly at the Marine Laboratory at Wood's Holl, Mass., and partly at the University of Pennsylvania.
The rapidly changing protoplasm is an evanescent structure to fix and classify, and camera drawing of the finest structure-phenomena the author finds impossible. "Of the living substance-phenomena," says the author, "it is about as practicable to reproduce it as it would be to trace upon a wall reflections thrown from disturbed water. Some camera drawings of the filose phenomena in starfish and ecchinus eggs were made, but such can show by direct tracing larger masses only of the substance and are in point of time and relation true but to a limited extent. It follows from the very nature of these phenomena, as will be seen, that they can not be traced; for while the