Page:Greek Biology and Medicine.djvu/136

 GREEK BIOLOGY AND MEDICINE process). Nutrition is an addition to these without expansion." The faculty of growth is present in the embryo, but subordinate to the genetic faculty until birth. Then, till the animal has reached its full size, the faculty of growth dominates while the alterative and nutritive faculties act as its handmaids. " What then, is the property of this faculty of growth? To extend in every direction that which has already come into existence, that is to say, the solid parts of the body, the arteries, veins, nerves, bones, carti- lages, membranes, ligaments, and the various simple and homogeneous coats of the stomach, intestines, arteries, etc." Galen then describes how children stretch and blow up pigs' bladders; but the bladders get thinner as they are expanded. The children cannot make the bladder get bigger, as only Nature can, through nourishment. " It will now, therefore, be clear to you that nutrition is a necessity for growing things. For if such bodies were distended, but not at the same time nourished, they would take on a false appearance of growth, but not a true growth. And further, to be distended in all directions belongs only to bodies whose growth [114]