'Judy Schloegel and Henning Schmidgen point to the prominence during the final decades of the nineteenth century of a physiological tradition in which the origins of psychological existence were associated with that of the most simple known forms of organic matter; in the work of Ernst Haeckel, Max Verworn, and Alfred Binet, psychological properties such as sensation, volition and intention were discovered in apparently primordial forms of life, most notably the cell. Though these investigators differed regarding the extent to which they regarded such properties as inhering in protoplasmic or nucleic parts of cells, all agreed that each could be considered an independent psychic unit.'