The union of the parts entering into the formation of the palate, alveolus, and lip is normally completed by the eighth to the tenth week, and when once this has occurred in these parts no maternal impression (such as seeing a gashed lip) could, as far as we know, bring about a retrogressive change. Should some shock occur to the mother prior to that period, we can fully appreciate the possibility of its interfering with the typical growth of the parts then being produced; and the fact that the due adjustment and union of so many component parts is requisite for the normal development of the mouth and face explains why these defects are relatively so common. That a severe shock to an infant may produce coincidently a lamellar cataract and defective development of dentine is well recognised; that a similar type of shock acting on the mother should result in defective union of parts developing at that period in the fœtus is not strange; but that the real shock and the so-called “Maternal Impression” are one and the same is more than doubtful. CHAPTER II. ANATOMY AND PHYSIOLOGY OF THE NORMAL PALATE. _The hard palate—The velum and its muscles—The mucous membrane—The blood supply—The shape and size of the hard palate—Functions._ The palate is a more or less horizontal partition dividing the month from the nasal cavity, and consists of a firm bony plate in front (the hard palate) with a freely moveable membrano-muscular velum behind (the soft palate), which under varying conditions of muscular action can either open or close the communication between the nose and pharynx.