Page:Popular Science Monthly Volume 33.djvu/803

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which have already been brought about as described, "fresh types of conduct gradually set into form and give rise to corresponding rules. These rules are the body of morals."[1] Nor is this all. As this conduct becomes habitual in the individual it affects him physiologically as well as psychologically, and through the changed cerebral structure which it produces, it is transmitted to his offspring, to become in the long process of the ages those moral intuitions which we group under the name of conscience. Note further that the kinds of conduct which our intuitions regard as authoritatively prescribed are such as long social contact has shown to be essential to the well-being of society, and that this same well-being furnishes us the test of our duty to fulfill obligations which for any reason have become ambiguous and indefinite. May we not conclude, then, that the fulfillment of duty to self and to society is the true end of economic action? If so, "let us bind love with duty, for duty is the love of law, and law is the nature of the Eternal."[2]


NOTHING is more strange in the history of evolution than the persistence of rudimentary structures, which have lost all usefulness untold generations ago, and in many cases have become absolutely dangerous to the organism. Among these survivals, one of the most curious is the pisiform bone of the wrist, which careful researches in comparative anatomy show to be the carpal or wrist bone belonging to a long-vanished sixth finger. The oldest mammals discovered have never more than five fingers. It is necessary to go back to amphibian forms to find a sixth finger, yet all mammals possess the wrist-bone formerly belonging to it. The pineal gland, once supposed, for want of a better hypothesis, to be the seat of the soul, is a still more curious instance of survival, inherited probably from some transparent invertebrate ancestor with a median eye.

In mammals the pineal gland is deeply sunk beneath the highly developed intellectual portion of the brain, in a position utterly cut off from all possible communication with the outer world. Human physiology alone would have left us utterly without a clew as to the original use of this mysterious body. The secret was discovered after long and patient study of the brains of amphibians and reptiles. In these animals the intellectual portion of the brain (cerebrum) is in a very undeveloped condition, and

  1. Martineau, "Types of Ethical Theory," vol. ii, p. 374.
  2. "Daniel Deronda," George Eliot, vol. ii, p. 335.