The widely advertised pastes and liquids for cleaning metal-work, particularly brass, often contain acids or alkalies that are injurious to metals. If after cleaning there should be a green deposit on brass or copper it will be wise to inquire into the composition of such deposit, and to discontinue the use of that paste or liquid. When brass pans are used for boiling fruit for jams, it is usual to rub them inside with a slice of lemon before putting in the fruit. A careful housewife will consider the reason for this custom. We remember once seeing a copper pan, that had been provided for the preparation of oatmeal porridge, with a band about an inch wide of green crystals on the inside. Inquiry elicited that the cook had thought it a convenient pan in which to prepare the fish (salt haddock) for breakfast. Ignorance of the chemical action of salt and acids on metals may lead to very serious results. The common name for the green deposit on brass and copper is verdigris, and most people know that verdigris is a poisonous compound; the difficulty is that, not knowing its chemical composition, they do not recognise verdigris when they see it. The cook thought that the complaint made had reference only to the misuse of the pan, and said that it was quite easy to clean the green deposit off! THE CHEMISTRY OF THE BODY It is to the science of chemistry that we owe our knowledge of the composition of the various foodstuffs from which dietaries are selected, as well as of the several parts of the human body which relies for its sustenance on those dietaries. But the adjustment of dietaries to the work they have to do is a more complex problem than those we have hitherto considered. We learn from the science of physiology that the human body is a laboratory in which certain juices are secreted for the digestion of foods, and that in this laboratory foods must be reduced to the consistency necessary for their passage through animal membranes; for it is by passage through membranes that the nutritive parts of food find their way into the general circulation of the blood which carries them to all parts of the system. Very few foodstuffs are available for use in their natural state, and the majority of them are prepared for consumption in the first place by more or less elaborate processes included in the art of cookery. When thus prepared they should be in a fit state to undergo in the body the physical changes comprised in mastication, and the chemical changes associated with the process of digestion.