"s and frogs and s, scurrying to cover as we approach the shore of a still clear pond, show us that the water has some very lively inhabitants. They swim and dive and paddle in the open until we come, and then they hide from us distrustfully. Theirs is another world than ours. In that world there are strange living creatures in endless variety. ... No one who has lived by clear waters can have failed to see something of their wonderful life: minnows on the shoals; s dragging their cumbersome portable houses over the brook bed ; the clinging to the stones in the riffle, or the adult in their dancing nuptial flight in the air above the stream; and what could be more interesting? To make the knowledge of the whole range of life in ponds and streams a little more easy of access ... is a public service of no small moment. It is all in the interest of a better human environment; better for health, for , for instruction, and for aesthetic pleasures."