Having disposed of the question, "what to eat," we will consider another matter, almost equally important, and that is: How To Eat. The one fundamental principle underlying this question is thorough mastication, and we cannot too strongly impress upon our readers the necessity for its proper observance. We have already stated that digestion cornmences in the mouth--that by the action of the saliva, the starchy matter in food is converted into glucose. It is therefore necessary that the saliva should be brought into intimate contact with every part of the bolus; and for that purpose thorough mastication is absolutely necessary. In addition, the separation of the food into small fragments, by the teeth, assists stomach digestion, by permitting the gastric juice freer access to the food. It is stated that Mr. Gladstone formed the habit of thorough mastication by making it a rule to count thirty two while masticating each mouthful. Mastication need not be slow to be thorough, although there is an impression to that effect, for, as a matter of fact, quick and vigorous chewing excites the salivary glands to more energetic action. Drinking at meals should be avoided as much as possible, and whenever any digestive trouble is present, not only should no liquids accompany the meal, but nothing in the form of fluids should be partaken of within half an hour preceding or following a meal, The philosophy of this is apparent, when we reflect that all digestive disturbances are accompanied by imperfect secretion of the gastric juices, and to dilute them with an excess of fluid is to weaken its power of action on the food. It is as if a man, when attempting to dissolve a piece of metal in a powerful acid, should deliberately add water to the acid, and thereby arrest, wholly or in part, the process of decomposition. It is plain, therefore, that although the practice of drinking at meals may help the food to pass more easily down the aesophagus, yet it must inevitably retard digestion when it reaches the stomach.