The frequent appearance of the "black sheep" in a flock of tolerably white sheep, the frequent failure of the best efforts of parents and teachers to make a fairly decent man out of a promising boy, have led many to question whether, after all, the pains and effort are worth while. We have come to question the wisdom of bothering about "environment"; just as we sometimes question the existence of a principle called "heredity." Every day some one asks the question, "Do you believe in heredity?" And many times a day people discuss, "Which is more important, heredity or environment?" These are certainly _practical_ questions for parents, since the answers we receive must influence our practice or conduct in relation to the children. If we felt quite sure that heredity was everything and environment nothing, we should reduce our school appropriations and build larger jails and asylums, or we should resign ourselves as best we could to letting "nature take her course." On the other hand, if we felt sure that heredity was nothing and environment everything, we should proceed at once to double our school equipment, raise the teachers' salaries, convert our penal institutions into reformatories and our armories into recreation centres, and advance the age of compulsory education just as far as we thought we could afford to. Those who place the emphasis upon heredity, in the attempt to discredit the value of thoughtful and painstaking control of the environment of the developing child, usually remind us that a man like Lincoln achieved power and distinction in spite of what we would ordinarily consider serious obstacles to complete development, whereas thousands of college graduates who have had all the advantages that trained tutors and guarded surroundings can give have developed into mediocre men and women--have even developed into vicious and criminal men and women. They will remind us that from a class of children that had the same teachers for many years has emerged a group of very distinct men and women; they will remind us that brothers and sisters with the identical "environment" turn out to be so different. On the other hand, those who see nothing in "heredity" will point to the same Lincoln and ask confidently why his ancestors and his descendants do not show the same degree of power and achievement. They will point to the same family of brothers and sisters who had the same "heredity" and ask why they all turned out so differently. The black sheep proves just as much--and just as little--for one side of the argument as it does for the other.