1. A simple chromatographic method for the study of porphyrins in erythrocytes and blood plasma, requiring little technician time, is described. The findings in adults and neonates are presented as well as those from severely ill patients.
2. The regular occurrence of uro-, copro- and proto-porphyrin in erythrocytes is demonstrable as well as sporadic occurrence of tri-, penta-, hexa- and hepta-carboxylic porphyrin. The method gives, however, irregular values for protoporphyrin, which seems to occur in a more labile form in some subjects than in others; this is especially the case in erythropoietic protoporphyria.
3. In blood plasma, uroporphyrin occurs regularly, and coproporphyrin less regularly. Protoporphyrin and penta- to hepta-carboxylic porphyrin are found only occasionally.