The characteristics of life exhibited in the lower grade of vegetation, are seen in a more perfect degree in animal life--respiration, exchange of gases, imbibition, absorption, assimilation, evolution of heat and motion, the power of incorporating material in its own substance, endosmosis, subjectibility to irritation, exhaustion, spontaneous movement, rest and sleep, capability of being influenced by various stimuli, etc., etc. The combination of O, C, and H, organized and vitalized, in conjunction with a few other less important elements, manifests in conformity with the laws of nature all functions and activities that plant lie is capable of realizing. It would neither be extravagant, nor an exaggeration, considering the important role these elements play in vegetation, if they were rightfully termed the soul-life of plants. CHAPTER XXII. ALCOHOL AND ITS EFFECTS ON THE SYSTEM. All substances taken into the stomach as food are of three kinds, carbohydrates, proteids, and fats. This means, starch, sugars, meats, and fats, besides water and some salts. Food substances carry their own complement of water, serve nutritive purposes when taken into the system, and are easily dissolved by the various fluids in the body. Food may be taken into the system for three purposes: 1. Simply for the maintenance of health; 2. For fattening purposes; 3. For the sake of muscular energy. The body, the human body, consists, speaking in general terms, of carbohydrates, fats, and proteids, and water and saline matters. We have seen that the work done by the master tissues causes a loss, or produces a certain amount of waste material, consisting of Carbon, Hydrogen, Oxygen, and Nitrogen, and some mineral matter--salts. This loss or waste has to be replaced in quantity and quality sufficient in order to maintain a healthy condition of the body. And, since we know the precise, or almost the precise, quantity of material excreted, which consists of Carbon, Nitrogen, Oxygen, and Hydrogen, etc., we can also estimate, with considerable precision, the quantity needed to replace it. More than 41 per cent of the entire weight of the body is made up of muscular tissue. The nervous tissue constitutes not quite two per cent. The chemical composition of muscular and nervous tissue--of the solid part only--is Carbon. Hydrogen. Nitrogen. Oxygen. Sul. 51.5 6.9 15.2 20.9 0.3 to to to to to 54.5 7.3 17.0 23.5 2.0 The watery portion of the muscle is not mentioned. Please notice the large quantity of Carbon and the small quantity of Hydrogen in the composition of the solid part of the muscle. We are aware that the muscles are always producing Carbonic Acid--that is, C and O2--and when a muscle contracts, there is a sudden and extensive increase of the normal production.