Dr. Ferguson made extensive observations on the little children of the factory operatives of Lancashire, Eng. The children were principally fed on tea or water and bread, little or no fat, bacon, butter or cream, and they grew up into puny and stunted men and women, while those who had a bread and milk diet grew into hardier and finer human specimens. Fat is also an essential food for the brain and general nervous system; the lean are the nervous patients and not the fat and sleek, hence fatty food is considered an important diet for this class of diseases. The brain and nerve fat is called “lecithin” and a little phosphorus enters into its composition. Chronic obstinate neuralgia has often been cured by the administration of cod liver oil. Milk is the only single article of diet which possesses in itself all the properties to supply the wants of the system, and it may be profitable to give this subject more than passing notice. It is the natural and most wholesome food for the infant when it can suck it from its mother’s breast; instinctively the newborn rolls its little head hither and thither in search for this fountain of infantile life and however great the skill of the chemist in approaching the composition of mother’s milk, he can never produce an equally good substitute. Milk contains all the principles which are necessary for human food, the nitrogenous, the oleaginous and the saccharine, and these are blended in such proportion that milk is adapted for the complete nourishment of the young and old. In no other single substance supplied by nature does a similar combination exist; it contains the material for the consolidation of bone and for the formation of the red blood corpuscles, by carrying in solution the phosphates of lime, magnesia and iron; in this respect an analysis of milk shows a remarkable similarity to blood. The proportions of the different constituents of milk are liable to great variations and are greatly influenced by the nature of the food. Dr. Playfair of London, who has made some interesting researches regarding the milk of the cow, has demonstrated that the amount of butter depends in part upon the quantity of oily matter in the food and in part on the amount of exercise which the animal takes; and upon the warmth of the atmosphere in which it is kept. Exercise and cold weather eliminate the oily matter or butter, in the form of carbonic acid and water, while rest and warmth diminish this drain by favoring its passage into milk. On the other hand, the proportion of the cheesy matter is increased by exercise. In Switzerland, where the cattle pasture in very exposed situations and where, from the rolling of the country, they are obliged to use a great deal of muscular exertion the quantity of butter yielded by the cows is very small, while the cheese is in unusually large proportions; but the same cattle when stall fed give a large quantity of butter and very little cheese.