Contents Page Introduction F Preparation of the samples Preparation of the resin column . Elution procedure . Identification of the nuclides present FP . Own in the fractions ll Results Sample I 13 Sample II a4 Discussion 49 Summary 54 Referencega 56 Appendix 29 Volumes in milliliters of eluted fractions obtained in the ion-exchange experiments 59 with Dowex 50. Volumes in milliliters of eluted fractions obtained in the Lon-exchange experiments with Dowex 1. 29 Summary of data and calculations on four 60 biological samples in which chemical separations were made. mi 2ame a re eae 1. Ww Materials and Methods