Popular literature abounds in unsound statements on food. It is unfortunate that many ardent workers in the cause of health are lacking in scientific knowledge, especially of physiology and chemistry. By their immature and sweeping statements from the platform and press, they often bring discredit on a good cause. Matters of health must be primarily based on experience and we must bear in mind that each person can at the most have full knowledge of himself alone, and to a less degree of his family and intimates. The general rules of health are applicable to all alike, but not in their details. Owing to individual imperfections of constitution, difference of temperament and environment, there is danger when one man attempts to measure others by his own standard. For the opinions here expressed I only must be held responsible, and not the Society publishing the pamphlet. Vegetarians, generally, place the humane as the highest reason for their practice, though the determining cause of the change from a flesh diet has been in most cases bad health. A vegetarian may be defined as one who abstains from all animals as food. The term animal is used in its proper scientific sense (comprising insects, molluscs, crustaceans, fish, etc.). Animal products are not excluded, though they are not considered really necessary. They are looked upon as a great convenience, whilst free from nearly all the objections appertaining to flesh food. A.W.D. The Chemistry of Food and Nutrition By A.W. DUNCAN, F.C.S. We may define a food to be any substance which will repair the functional waste of the body, increase its growth, or maintain the heat, muscular, and nervous energy. In its most comprehensive sense, the oxygen of the air is a food; as although it is admitted by the lungs, it passes into the blood, and there re-acts upon the other food which has passed through the stomach. It is usual, however, to restrict the term food to such nutriment as enters the body by the intestinal canal. Water is often spoken of as being distinct from food, but for this there is no sufficient reason. Many popular writers have divided foods into flesh-formers, heat-givers, and bone-formers. Although attractive from its simplicity, this classification will not bear criticism. Flesh-formers are also heat-givers. Only a portion of the mineral matter goes to form bone. Class I.--INORGANIC COMPOUNDS. Sub-class 1. Water. 2. Mineral Matter or Salts. Class II--ORGANIC COMPOUNDS. 1. Non-Nitrogeneous or Ternary Compounds. _a_ Carbohydrates. _b_ Oils. _c_ Organic Acids. 2. Nitrogenous Compounds. _a_ Proteids. _b_ Osseids. Class III.--NON-NUTRITIVES, FOOD ADJUNCTS AND DRUGS. Essential Oils, Alkaloids, Extractives, Alcohol, &c. These last are not strictly foods, if we keep to the definition already given; but they are consumed with the true foods or nutrients, comprised in the other two classes, and cannot well be excluded from consideration.