Abstract
THE earlier classifications of porphyria, notably those of Günther1 and Waldenström,2 were purely clinical in character. The former included congenital, acute and chronic varieties; the latter differed only in substituting the term "cutanea tarda" for "chronic." In some respects this substitution was advantageous, and indeed the term "porphyria cutanea tarda" has come into rather general usage; in certain respects, as noted below, it is disadvantageous.Studies with Schmid and Schwartz3 , 4 revealed striking differences in porphyrin and porphobilinogen content of the liver and bone marrow in the various forms of the disease. Thus, it became clear that Günther's congenital type is . . .