"As non-scientists, most gardeners deprived of atomic-ray spectrometers, a battery of reagents, and a few million research dollars must look to signs of health such as the birds, reptiles, worms, and plants of their garden-farm. For myself, in a truly natural garden I have come to expect to see, hear, and find evidence of abundant vertebrate life. This, and this alone, assures me that invertebrates still thrive there. I know of many farms where neither birds nor worms exist, and I suspect that their products are dangerous to all life forms."