In time, however, progress set in, and social reformers began the great movement for the betterment of the environment, sanitation, shorter hours of labor, and restriction of child-labor, factory regulation, etc. And when the environment is bettered, the death-rate drops, and the birth-rate accompanies it on its downward progress. As Leroy-Beaulieu says: "The first degree of prosperity in a rude population with few needs tends toward prolificness of reproduction; a later degree of prosperity, accompanied by all the feelings and ideas stimulated by the reduction of such prolificness." The law of the reduction of reproduction in response to the improvement of environment is a natural law, arising from fixed biological principles. This is because when we improve the environment we improve the individual situated in that environment; and the improvement of the individual has always resulted in a check upon reproduction. We must remember, however, that this change is not the result of conscious or voluntary action; instead it is the result of unconscious activities and instinctive urge. As Sir Shirley Murphy has said: "Birth Control is a natural process, and though in civilized men, endowed with high intelligence, it necessarily works in some measure voluntarily and deliberately, it is probable that it also works, as in the evolution of the lower animals, to some extent automatically." Science shows us that even among the most primitive micro-organisms; when placed under unfavorable conditions as to food and environment, they tend to pass into a reproductive phase and by sporulation or otherwise begin to produce new individuals rapidly. This, of course, because of the fact that their death-rate is increased, and an increased birth-rate must be manifested in order to maintain a balance. If the environment be improved, the death-rate decreases, and this is followed by a fall in the birth-rate, according to the constant laws of Nature manifesting in such cases. The same law is seen to be manifested in the case of Man. Improve his environment, and his death-rate drops, which is accompanied by a falling birth-rate. Here, once more we see the application of the scientific axiom "Improve the environment and reproduction is checked." As Leroy-Beaulieu has said: "The tendency of civilization is to reduce the birth-rate." And as Professor Benjamin Moore has said: "Decreased reproduction is the simple biological reply to good economic conditions." And as Havelock Ellis has said: "Those who desire a higher birth-rate are desiring, whether they know it or not, the increase of poverty, ignorance, and wretchedness."