The combination and exchange of elements takes place in the simple plant life as in the higher animal life. The watery portion of plant life is composed of O and H2, the same as water in a free state or water in animal life, and the combination of Oxygen and Hydrogen with Carbon. The food substances are found in the vital machinery of vegetation.
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.