THE ENVIRONMENT LIFE is series of reactions upon environment. In other words, the self-existent principle of life perpetuates itself by reacting upon natural forces which play upon it. Just as the life-principle in the plant reacts upon the chemical elements of the soil, the air, sunshine, heat, and moisture, so the life-principle in man reacts upon and thus a**imilates food, drink, air, light, heat, etc., which are elements of his environment. And man is as dependent upon these natural elements as is every other living being. To ignore it, to deny the part it plays in his existence, is to cut the ground from under his feet. For man is not an isolated fact of nature. p. 74 [paragraph continues] "He is as much a part of the cosmos," says Huxley, "as the humblest weed"; and like the seed sown upon stony ground which can not spring up and put forth, he can not attain his best development amid unfavorable conditions. Experience has taught him that certain elements are necessary to sustain life: pure air, pure water, pure food, sunshine; and given these constituents in proper proportion, there exists a sound basis for health, as the automatic activity of the brain and nervous system controls a**imilation and nutrition. But if through negligence, ignorance, poverty, or a wrong habit of life, one or more of these elements are lacking or inferior in quality there result impoverished blood and enfeebled vitality. Now the common sense of every person should tell him that no mental power can reinstate health if the environment is unfavorable or the laws of hygiene are constantly p. 75 violated. Man is finite, not infinite; hence the human mind can work no miracles. It works successfully only in harmony with nature's laws; but the operation of those laws may be a**isted by intelligent adaptation to the environment. This gives free play to that healing force of nature--called by medical men vis medicatrix naturæ--implanted in every living thing. Thus the bruised plant, the sick or wounded animal, through its agency, regain their normal state; the surgeon sets the broken bone, but nature reunites the severed parts. And this is a cosmic force, ever struggling to reinstate health and preserve life; and in many cases it will do so, without other aid, if the sufferer will a**ist nature by the exercise of intelligence and self-control. It must not be forgotten, however, that there is a mental as well as a physical reaction upon external forces. Man is p. 76 a two-sided phenomenon, on the one side mental, on the other physical. Both are important factors in the equation; both are essential to his existence as a human being. But while no amount of thinking will change impure air into wholesome air, or avert its pernicious effect, or render adulterated food nutritious, yet there are cases where the mental reaction is so poor that even the best conditions fail to conserve health. Take the "grouchy" man, for instance, who complains that his food is not well cooked or else indigestible; who grumbles at the weather, at the streets, at the transportation companies, at his neighbors, his family, etc. Such a man would be neither well nor happy in the Garden of Eden, for his mental reaction upon life is morbid and the effect of this upon all physical processes vicious. The fact is one may get such into a p. 77 [paragraph continues] "state of mind" as to pervert all of nature's processes and nullify not only the spontaneous effort of nature to preserve life and health but every hygienic and medical agency which can be employed. And so, when all is said, we must conclude that the mental reaction is as important as the physical. Life is a double reaction upon nature--or a two-sided phenomenon; both sides are necessary to the perfect whole. But the real essentials of life on the physical side are few: air, water, sunshine and food, shelter and clothing. Of these, the first three are, generally speaking, the gifts of nature; and a**uming that they are within reach, then one may by intelligent effort so mold and adapt himself to conditions, or so improve conditions, as to attain both health and happiness. Some of the world's greatest leaders flowered from poverty and squalor.