A contribution to the knowledge of the so-called pyloric band ("double pylorus").

Two new cases of patients with so called muscular pyloric band ("double pylorus") are reported. Both possible genetic mechanisms of this malformation are discussed in detail: primary or congenital, and secondary or acquired by inflammation. After analysis of the hitherto related cases, the opinion is expressed that the so called pyloric band represents a congenital malformation. According to the authors, the striking frequency of simultaneous occurrence of pyloric band and ulcers does not necessarily favour the theory of inflammatory genesis. The accompanying ulcer seems rather to be a "second disease" in the sense of Rossle (1913), manifesting itself at a locus minoris resistentiae.