ABSTRACT
SO far we have been thinking of not-living things and powers, now we pass to living creatures or organisms. They consist, it is true, of matter, and their life involves continual transformations of energy, so that there is a chemistry and a physics of the living body, whether of plant or animal or man. Yet their activities are in many ways different from those of rivers and tides, planets and stars; they are individuals that feed and grow and multiply, that wind themselves up when they run down, that struggle and get things done, that often change a little from generation to generation. Sometimes it is quite plain, as in horse and dog, that they have a mind of their own. Thus a special science is required—the science of Biology, which has various subdivisions, such as Botany and Zoology.
