“…As th e patien ts in every group are from the same m aterial, hardly differing from one another as regards age, sex, hom e and occupation [3,5,15,19,24,27,37,39,40,44,46,47,48,49,50], the differences of hypersensitivity of th e several groups cannot be explained by exter nal factors. Therefore, we m ay suppose th a t the skin diseases and the in ten sity (frequency) of hypersensitivity have some correlation.…”