It might be surmised by the thoughtful parent that as the child's body lacks some of the external features of the adult body, such as hair and teeth, so there might, and probably would, be corresponding lapses in the internal economy, and that therefore the food prepared for the adult would be, even in the smallest quantity, unsuited to the child. Physiologists tell us that this is so, and in particular that the secretions which in adult life are called saliva and pancreatic juice and which have the function of preparing starch for digestion, are at this time scanty in amount and deficient in chemical action. But these secretions are essential for the digestion of starchy foods, and chemists tell us that starch abounds in the vegetable kingdom from which most of the food of children is derived. It is therefore a matter of some importance that every person in charge of an infant should have that amount of knowledge of chemical reactions which is requisite to enable them to detect whether a food does or does not contain starch. A child fed entirely on starchy foods suffers from malnutrition of so serious a character that death may, and often does, ensue. Even if other suitable food, such as modified milk, be given, the internal economy of the child will be seriously disturbed. The names by which patent foods are advertised are very often misleading to unscientific persons, and invalids have suffered much from the mistaken idea that jellies and meat extracts are foods. Meat extracts have their use, but any invalid fed on extract of beef only would die sooner than one left with no food at all. The reason for this can be learned from the knowledge of the constituents of beef extracts and the part they play in the human organism. CONCLUSION If we have seemed to lay stress on the value of a knowledge of the sciences of physics and chemistry to the exclusion of the mention of others, our justification of the fact is that space is limited, and that we believe that physics and chemistry underlie all the other sciences and are of paramount importance to students of all other subjects. In the sciences of biology, physiology, botany, geology, &c., little advance can be made without a knowledge of the fundamental laws of nature. The physical laws control movement, and the chemical laws control growth, whether of animate or inanimate nature. Physical and chemical phenomena are concerned in the upheaval of rocks and mountains which govern the contour of the continents of the world. These contours influence climates and peoples; as the contours change the people change. The dwellers in the mountain regions differ in character from the dwellers in valleys and plains; the inhabitants of cold districts differ from the inhabitants of warm districts; but it is people who make history, and historians cannot afford to pass by natural environments and natural laws.