The civic nature of these problems is appreciated when we realize that it would do little good, for example, for one person to destroy the breeding-places of mosquitoes on his premises, if his neighbors did not do likewise about their homes; or for one orchardist to cut out the blight from his pear-trees or the black-knot from his plum-trees, if his neighbors did not co-operate with him by ridding their orchards of these diseases. These practical questions are so well presented, together with plans for their solution, in _Civic Biology_, by Clifton F. Hodge and Jean Dawson (Ginn & Co.), that instead of going into details here, both the _Girl Scouts_ and their Leaders are referred to this most useful work. All objects of Nature are either living (organic) or non-living (inorganic). The non-living bodies include the minerals and rocks. The living bodies are either plants or animals. Plants may be divided into two great groups, the flowerless plants and flowering plants. In general the flowerless plants reproduce by means of spores, like the mushroom and the ferns, while the flowering plants reproduce by means of seeds. [Illustration: ROCKY MOUNTAIN GOAT This animal is really not a goat, but is more nearly related to the antelopes. Range: The higher mountains from Alaska south to California. Group in American Museum of Natural History.] Animals may be separated into two great groups, those without backbones (invertebrates) like an oyster, a cricket, or an earthworm, and those with backbones, e.g., a dog, a fish. In this brief study we shall not go into much detail about invertebrates, but with the backboned animals or vertebrates we shall go a little further. These may be divided into five general groups: (1) Fishes; (2) Amphibians, which include frogs, toads, and salamanders; (3) Reptiles, which include alligators, crocodiles, turtles, lizards, and snakes; (4) Birds; (5) Mammals. This simple analysis may be clearly shown by the following diagram: {_Mammals_ {_Birds_ {_Vertebrates_{_Reptiles_ { {_Amphibians_ { {_Fishes_ {_Animals_{ { {_Invertebrates_ {_Living Bodies_{ { (_Organic_) { {_Flowering Plants_ _Objects_{ { {_Flowerless Plants_ _of_ { _Nature_ {_Non-living Bodies_ { (_Inorganic_) This classification could be carried further at every point, but this will be far enough for present purposes. It should be remembered in any classification that there are no hard and fast lines in Nature. For example, some creatures are on the border-land between plants and animals, and again some animals are between the backboned animals and those without backbones.