It is absolutely necessary that he who ventures to interfere with a person's diet should first understand the principles upon which the food of health is regulated in nature; and nothing more assists the intelligent doctor in getting his orders carried out, than for his patient, as well as himself, to be acquainted with this subject. Ignorance and stupidity are the constant obstacles in the proper regulation of these matters. To elucidate this part of the subject, I have drawn up a brief statement of the "Essentials of a normal diet." (See Chapter III (What Do You Need For A Normal Diet).) This is illustrated by a set of tables, showing the method by which diets may be arranged so that they shall equally well support the human body in a state of normal health and strength, whether they consist of a complicated list of expensive articles, or of no more than Bread, Cheese, Butter, Cresses and Water. In addition to this I have introduced a chapter "On the wholesomeness and digestibility of various articles of food " (Chapter V (On The Wholesomeness And Digestibility Of Various Articles Of Food And On The Modes Of Cooking In Common Use).), " On the diet of infancy and childhood " (Chapter IV (On The Diet And Regimen Of Children).), and " On fat and starch in the nutrition of children" (Chapter VII (What You Need To Know About Fat In Nutrition)).

The advances of science have, of late, thrown most important light upon the connection between food and force, a subject of the greatest interest to all, whether medical or not; for, as we all take food and all desire to be strong, we are unavoidably fascinated by the inquiry what kind of food will give us the greatest amount of force. I have, therefore, introduced a short chapter "On Food, Heat, and Motion." (Chapter II (The Relationship Between Food, Heat, And Motion).)

The question of "getting fat or getting thin," whether in health or disease, is one inseparable from the subject of food and force; for we have discovered that heat is but a mode of motion, and that those elements of food capable of liberating the largest amount of heat, may be utilised as accumulators of fat by economising the motion and heat of the body, and vice versa. In the Chapter "On Food, Heat, and Motion," I have introduced a table, showing the composition of some of the most important articles of food, and the amount of heat to be got out of equal quantities of each, and I have also stated the amount of mechanical force equivalent to a given quantity of heat. In order to elucidate the importance of fat, and the subject of getting fat or losing fat by alterations of diet, I have introduced some remarks on "Bantingism," on the means which promote the accumulation of fat, and on the importance of distinguishing between solid and liquid fat. (See Chapter VII (What You Need To Know About Fat In Nutrition).)

From what I have already said, and from the articles referred to, it must be clear that nothing can take precedence of proper food among the means for the preservation of the public health; and when health is lost, whether by unavoidable disease or by other causes, nothing can be more important than to understand the leading principles which should guide us in altering the food to meet the conditions of disease, and thus to con vert diet into a powerful instrument for the restoration of health. This is a subject which could not be fully discussed in a small work like the present, but in Chapter VI (Some Principles Of Diet In Disease)., "On some principles of Diet in Disease," I have given some rules for the regulation of the food in various diseases, illustrated by Diet Tables for Consumption and for Diabetes.

The subject of Alcohol, which has of late years occupied so much attention, both in the scientific and in the religious world, and which has been so grievously misrepresented and misunderstood, is now placed upon a more reasonable footing, some plain facts having been unquestionably established by the dispassionate investigations of practical and scientific men. In this country we are particularly indebted to Dr. Anstie and Dr. Parkes for their investigations on this subject. (See Appendix.)

It is now quite certain, as I have long maintained, that alcohol is food - that is to say, that it is consumed in the body by a process of oxidation similar to that which other kinds of food undergo, that during its combustion force is liberated and the demand for other kinds of food diminished. Alcohol, therefore, is able to save the combustion of the elements of tissue formation, by vicarious oxidation of itself.

It is quite certain that alcohol is one of the most readily oxidisable substances capable of being introduced into the animal organism. In this consists its chief value and its chief danger; for, on the one hand, it is able to replenish the lamp of life with so little tax upon the digestive functions, and with so little loss of time, that nothing can take its place when these are the desiderata of most urgent import. But, on the other hand, this ex traordinary facility for oxidation makes the presence of alcohol in the system a most dangerous impediment to the combustion of those less readily oxidisable matters, the full and regular combustion of which is absolutely essential to the continuance of normal health.

It is quite certain that alcohol is not an indispensable article of daily food; a normal diet may be perfectly well constructed without it, and a healthy person, under favourable circumstances, can live without it, just in fact as the lower animals do. But it is also quite certain that alcohol is a most blessed gift of Providence, when rightly understood and wisely used. It is the endowment of man with those higher attributes which principally distinguish him from the brutes, that constitutes the element in his nature which has made it necessary to his welfare that Providence should give him this peculiar article of food, in addition to all those placed within the reach of the less intellectual animals.

Thus it is a fact, that while man is brutalised by the abuse of alcohol, its proper use is one of his distinctions from the brutes.

Alcohol may, perhaps, be best described as a Medicinal Food. It is essentially a poison, although in its proper use it is an indispensable element in the life and happiness of highly civilised society. But it ought always to be regarded as a most treacherous friend.