This article will deal only with the phonology of the problem. By a careful study of the Spanish and French forms I hope to establish the correct etymologies of the important forms and to show that we must suppose for Vulgar Latin a form metīpsimus by the side of As I have said in my Studies in New Mexican Spanish, the majority of the explanations previously given for the various forms in Spanish and French, are curious rather than scientific. Gaston Paris (Extraits de la Chanson de Roland, § 18), Cornu (Rom. xiii, 289) and Menéndez Pidal (Gram. Hist., § 66), however, seem to have come to believe in a long vowel for some of the forms and rightly so. As to the numerous attempts made by others, it is only necessary to say, that in so far as the Spanish and French forms are concerned, every explanation which the writer has seen is either a traditional error or a new one. Such explanations as those of Baist (Grundriss, i, 887, and Krit. Jahrsb., i, 534), Cejad or (La Leng. de Cervantes, i, 739), Cuervo (Apuntaciones, § 777), Ford (Don Quixote, 93), Pieri (ZRPh., xxvii, 584) and others for the Spanish forms, and of Mussafia (Rom., xxviii, 112), Etzrodt (Rom. Forseh., xxvii, 878), Harseim (Boehmer Stud., iv, 287) and others for the French forms have little or no basis in fact and I need not refute them here.