Ecological study does not end with collecting specimens, and it may not begin there. The importance of collecting and preserving specimens will vary with the phase of ecological study considered. In the field study of behavior of a single species there may be almost no collecting of animals but much collecting of notes; but if one is devoted primarily to the recognition and study of the composition of associations and their interrelations, much collecting will have to be done. Also, when studying the ecological relations of some taxonomic unit, as in aggregate ecology, the number of associates is so large that one must do rather extensive collecting. But even the exhaustive study of the behavior of any single species will necessitate considerable collecting. The necessity for this has been shown by Forbes (1880, The Food of Fishes, p. 20) as follows: “If one wishes to become acquainted with the black bass, for example, he will learn but little if he limits himself to that species. He must evidently study also the species upon which it depends for its existence, and the various conditions upon which _these_ depend. He must likewise study the species with which it comes in competition, and the entire system of conditions affecting their prosperity. Leaving out any of these, he is like one who undertakes to make out the construction of a watch, but overlooks one wheel; and by the time he has studied all these sufficiently, he will find that he has run through the whole complicated mechanism of the aquatic life of the locality, both animal and vegetable, of which his species forms but a single element.”