The following typographical errors have been corrected:
Page 180 "Abfällen, Vieweg, Braunschweig," - had "Viewig".
Page 188 "wires d from the dynamo D" - had "dynano".
Page 192 "But phosphatides occur" - had "phosphatide soccur".
Page 193 "the nucleic acid from the thymus" - had "nucleidic".
Page 199 "acetylcholine esterase." - had "acetylcholin".
Page 200 "George de Hevesy, Carl F. Cori," - comma added after Hevesy.