 In 1895 and 1896 Gadow and his wife made two journeys along northern Spain, from the Basque Country to Galicia.In 1897 Gadow published "In Northern Spain", the book that gathered together the very interesting observations on geography, ethnography, and fauna and flora he had made.Gadow's publications included "Classification of the Vertebra" (1898), a translation of Haeckel's work entitled "The Last Link" (1898) and the articles on anatomy in Alfred Newton's "Dictionary of Birds".