Thesis (Ph. D.)--University of Chicago, 1922. / "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." "Reprinted from the Biological bulletin, vol. XLIV, no. 3, March, 1923." Bibliography: p. 151-152. Also available on the Internet.

Thesis (PH. D)--University of Chicago, 1921. / "Author's abstract of this paper issued by the [Wistar institute] Bibliographic service, May 1." "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." "Reprinted from the Journal of experimental zoology, vol. 36, no. 1, July, 1922." Bibliography: p. 46-47. Also available on the Internet.

Bioelectric fields are involved in patterning during embryonic development and play roles in regenerative growth and wound healing. Planaria are flatworms capable of regenerating whole new intact organisms from tiny portions of tissue, owing to a widespread population of adult somatic stem cells known as neoblasts. Previous research has suggested that an endogenous bioelectric field may contribute to the control of axial polarity and regenerative fate during planarian regeneration. By establishing novel techniques, we further investigated this hypothesis in experimentally relevant planarian species Dugesia japonica and Schmidtea mediterranea. Techniques were developed to measure transepithelial potential (TEP), record epithelial ion transport and apply exogenous electric fields to test the hypothesis that an endogenous electrical gradient contributes to axial regenerative polarity in planaria. We found that in the mesenchymal spaces of Dugesia japonica and Schmidtea mediterranea, a voltage gradient exists such that the head region is more negative than the tail. Importantly, this voltage gradient is maintained in regenerating amputated tissue fragments. Disrupting this endogenous electric field by means of exogenous DC electric field application induced regenerative anomalies affecting the anteroposterior axis. Reversal of the TEP gradient and regenerative polarity was achieved by application of an electric field that opposed the direction of the worm's natural electrical polarity, suggesting that the natural electrical gradient contributes to the control of polarity establishment during planarian regeneration.