The Change of Colour in Milk, by Alkalies, from White to Red, gives a very evident Reason for the easy Transmutation of the Chyle into Blood, when it leaves its vegetable Nature, and puts on an Animal one; and is a further Confirmation of the Doctrine hitherto laid down. The Appearances that are observable in the Changes Milk undergoes, when left to itself, instruct us in the Choice of such kind as is most proper for Nourishment; which is principally to be regarded, where the Animal is entirely fed with Milk, which is the Case of Children at the Breast; and what happens to Children, may with proper Allowances be applied to older Bodies. If a Nurse feed entirely upon Flesh Meats, Fish, and Broths, or be hot and feverish, or use much or violent Exercise, some of which often happen to be the Case in wealthy Families, the Milk grows Yellowish, and by standing will turn rancid, the Child manifests an Aversion to it, and becomes hot, red, and feverish; on the contrary, if the Nurses Food be too much enclined to Acidity, which is often the Case of poor People, the Child shall be subject to Flatulencies, preternatural Distention of the Body, and paleness of the Flesh: The Milk for Food ought to be perfectly white and clear, the Animal that gives it, not suffered to fast long before, and used for Food as soon as possible after it is milked; for thus it is had in its most perfect and natural State. Before I leave the History of Diet, I cannot but take Notice, that as much Irregularity is committed in the Quantity, and Time of taking our Food, as in the Qualities or Properties thereof. From what hath been said it appears, that true Nutrition consists in the proper Assimilation of the Food to the Vegetable, or animal Body that takes it in; if the Powers of the Body be sufficient to assimilate what it takes in in a proper Manner, and to throw forth what it doth not need, or what is unfit for Assimilation, let the Food be what it will, the Body will be well nourished; on the contrary, if what be taken in be too strong to be changed by the digestive Powers, or the Powers of the Body too weak to expell it, that Body must be changed to a bad Habit; which, in its utmost Degree, is the Case of Plants and Animals that are poisoned. If the Body be oppressed with Loads of the most proper Food, more than the digestive Powers are able to deal with, or than there are animal juices sufficient to mix with for the proper Assimilation; those Powers must be weakened, the Fibres, being stretched beyond their Tone, lose of their Force, and what Foods are taken in, not being sufficiently acted upon by the Solids or Fluids of the Body, take the Course they would naturally have done out of the Body, and turn to Corruption, and Humour. When this happens to be the Case in human Bodies, upon a Stoppage of any of the great Discharges, as of Perspiration, by taking Cold, they become Subject to Fevers, and other acute Diseases, and Obstructions of the tender Bowels, chiefly