The question as to the ossification of the intermaxilla has been purposely omitted hitherto, that the subject and its morphological relationship to congenital deformities might be more fully discussed. In the time of Galen[44] the presence of the intermaxilla as a separate bone had been demonstrated in apes and lower animals, and its existence in man inferred, although probably not actually seen. This opinion held its ground till the sixteenth century, when Vesalius attacked it, maintaining that no such bone existed in man, and its absence was even claimed as a distinguishing feature from the lower animals. The first to actually discover and notify the separate existence of the bone in the human skull was Dr. Robert Nesbitt,[45] who, in a lecture before the Royal College of Surgeons in 1736, described and figured the suture crossing the anterior part of the palate at all times of life, and maintained that during intra-uterine life each superior maxilla “is generally divided into two distinct parts, the sutural line running from between the dentes canini and incisivi up to the bottom of the nose.” But the merit of appreciating the importance of this fact belongs to Goethe[46] and Vicq d’Azyr,[47] the former of whom, in the year 1779, demonstrated the existence of the intermaxilla in the human fœtus, and, as the outcome of this discovery, promulgated in 1819 the theory that in alveolar harelip the cleft in the alveolus occurs at the maxillo-intermaxillary suture, _i. e._ between the lateral incisor tooth and the canine. This opinion has been believed and handed down through successive generations of surgeons until the present day, but more recent and exact research has so increased our knowledge that it cannot now be considered correct. Many painstaking embryologists have, during the last ten years, been investigating this subject; but the honour of raising the question as to the morphological position of the cleft in harelip lies with Professor Albrecht of Brussels, who in a masterly series of papers has fully established the fact, observed also by others, that the intermaxilla is not developed _en masse_, but is formed by the coalescence of _four_ segments, two on either side; and he maintains that the cleft in alveolar harelip lies not between the maxilla and intermaxilla, but between the inner and outer intermaxillary segments. These have been named respectively the endo- and meso-gnathion, whilst the maxilla proper is called the exognathion. According to Albrecht, therefore, the cleft is not situated along the exo-mesognathic, but along the endo-mesognathic suture. Much controversy has been lighted up by this pronouncement, but here only a few of the points of interest and importance will be discussed.