'Though the notion that the body was permeated by a fibrous network of nerves through which organs communicated had been prominent in physiology prior to the nineteenth century, this had been sidelined as the cell theory had been established. In 1869 however, Thomas Henry Huxley had prominently declared protoplasm the 'physical basis of life'. First propounded by Max Schultze in 1860, it had been Haeckel who presented the most influential discussion of its relevance to psychology. As Robert Brain notes, Haeckel's contention that that protoplasm 'had the ability to receive and maintain the waveform vibrations of the external world' and thereby pass on organic characteristics from one generation to the next achieved great prominence during the late nineteenth and early twentieth centuries.'