Some fats are said to be wholesome and others are not, and the statement becomes intelligible when we study the process of fat digestion. This occurs, in its initial stage, probably in the duodenum, where the fat is split into fatty acids and glycerine, which, upon being absorbed by the cells and small intestine, are immediately reconverted into fat and reach the blood through the lymphatics. It is not then built up into the cell substance like protein, but deposited in the areolar tissue, and hence is very similar in appearance to the fat used in the food. Experience has shown that the fat of hay-fed horses is soon dissipated, and in like manner the adipose tissue which is quickly manufactured during a course of cod-liver oil rapidly melts away when its administration is stopped. Mutton fat, on the other hand, is firm and solid, and when used as a dietetic agency by those having a phthisical tendency, is the progenitor of a much firmer and more lasting adipose tissue.

It may be mere fancy to imagine that the nature of the subcutaneous fat has any significance of value in such patients, although it has always appeared to me to have, but in any case simple accumulation of fat globules in the tissues is a factor of very little importance in tuberculosis. Fat is, at the best, only an indication that the nutritional functions are in working order, and its rapid evanescence with little ultimate benefit to the tissues gives us reasonable ground for inferring that different forms of fat have different values in the economy. Breeders of stock certainly believe this, and aim at the production of firm fat, which will not vanish in the form of liquid grease on cooking, and any one who has experienced the inferior staying power of American bacon as compared with our home-grown product will have no difficulty in assenting to this proposition.

By proper feeding Weir Mitchell declares that during a rest cure fat appears first on the face and neck, then on the back and flanks, thereafter on the abdomen, and last of all on the limbs - the legs particularly being very tardy in acquiring a deposit. In everyday life one is accustomed to note in the obese that fat first accumulates on the abdominal wall, but, doubtless, this is accounted for by the fact that the muscles of this region are so little used in proportion to those in other parts of the body, and the active and continued use of any set of muscles directly reduces any adipose matter in their immediate neighbourhood. The inference is that fat is in a continual state of removal, being deposited from the blood and again absorbed by the muscles in their daily activities.