Notes from William Ballard's lecture. Trinkaus takes notes on different experiments on regeneration including information on "Poisons" and "Electricity"Lecturer: W. W. Ballard, Lecture "Polarity problems in Coelenterate Development" (Information taken from the 1939 Embryology Course Book)Page 56 of 72 from the second notebook of lecture and laboratory notes that John P. Trinkaus took during his time as a student in the Marine Biological Laboratory Embryology Course in 1939 in Woods Hole, MA