[Weal-formation by Utrica Dioica. An intravital reaction? (author's transl)].

The question concerning the intravital and postmortal mechanism of urticarial weal after contact with nettles (urtica dioica) was investigated in corpses, animal experiments and voluntary trials. No nettle weals could be induced in corpses or postmortally in experiments with albino rats (Witstar Strain). When animals were exposed to nettle-stings immediately before decapitation only 2 od 12 rats developed weals postmortally. However, the diameter of such weals was only 30% of that of weals produced intravitally. After Application of a tourniquet (180 - 200 mm Hg) to test persons no weals were formed after contact with nettles in a period of 10 minutes. As soon as the tourniquet was released weal-formation occured in full extent in most test persons. According to the authors opinion the occurence of nettle weals (urtica dioica) in corpses is therefore considered a local intravital reaction.