[Since the publication of Van Someren’s paper, “Was Luigi Cornaro Right?”, read before the British Medical Association, and reprinted elsewhere in this volume, much more attention has been given to the study of mastication than had been previously reported. Mr. Gladstone’s advice to his children, which was commonly current and was repeated whenever mastication was mentioned, was usually accompanied and met by an amused smile that showed that the full importance of better mouth-treatment of food was not appreciated. _Glutton or Epicure_, a little book by the present writer, published in 1898, insisted on thorough use of the functions of the mouth in alimentation but did not go into the anatomical, physiological and dental details. Dr. Harry Campbell of Northwest London Hospital has performed this latter service to science and humanity, with splendid carefulness, and must have devoted much time and study to the collection of evidence and suggestion which is given here following in full, reprinted from the _London Lancet_. The authors acknowledge with much gratitude, the courteous permission of both Dr. Campbell and of the editor of the _Lancet_, to reprint all four articles which composed the series. In our own study of the subject of mouth-treatment of food we have been led to give more credit to the chemical feature of preparation than Dr. Campbell yet attributes to the chemical side of the problem. Comminution of hard food is of first importance, undoubtedly, but insalivation and neutralisation or alkalinisation are, seemingly, much more easily and quickly accomplished in the mouth than farther on in the alimentary canal. The intestines _can_ do all in the way of digestion, even if the mouth and stomach are passed and their assistance in the digestive process is entirely neglected, but it is done at tremendous disadvantage in the supplementary digestive tract of the intestines. We have proven the economy of letting the mouth do _all it can_, by the insalivation (sipping and tasting) of liquids that have taste up to the point of compulsory swallowing (a sucking-up by the Swallowing Impulse which naturally occurs in the course of treatment in the mouth if not fought against too strongly). If Dr. Campbell will extend his observations to liquids, say milk, and for a sufficiently long time to measure results by continued economy of assimilation and saving of solid excreta, he will find that it pays to let the mouth do all it can do, and that while it _cannot do too much_ it _may do too little_. The natural instincts of the mouth, or those that attach to the mouth, become much more discriminating also if exercised on liquids as well as on solids. This they do not learn to do so well if sapid liquids are habitually rushed past their field of discrimination.