Page:Popular Science Monthly Volume 32.djvu/27

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17
AGASSIZ AND EVOLUTION.

The evidence, therefore, warrants the belief that the fall in recent years in the price of Indian wheat, and its consequent appearance as an important element of supply in European markets, is to be accounted for mainly, if not entirely, by changes in the conditions of its production and supply, and not by any changes in the relative values of gold and silver; and further, that if every measure for extending the monetary use of silver, which has been proposed, should be carried out to the fullest extent, it would produce no sensible influence in restraining the Indian ryot from competing with American and European agriculturists in the sale of wheat in the world's markets.


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AGASSIZ AND EVOLUTION.[1]

By Professor JOSEPH LE CONTE.

IN order to clear up the conception of evolution, it is necessary to give a brief history of the idea, and especially to explain the relation of Louis Agassiz to that theory. This is the more necessary, because there is a deep and wide-spread misunderstanding on this subject, and thus scant justice has been done our great naturalist, especially by the English and Germans; and also because this relation is an admirable illustration of an important principle in scientific philosophy.

Like all great ideas, we find the first germs of this in Greek philosophy, in the cosmic speculations of Thales and Pythagoras. Next (about 100 b. c.) we find it more clearly expressed by the Roman thinker, Lucretius, in his great philosophic poem entitled "De Rerura Natura." After a dormancy of nearly eighteen centuries it next emerges with still more clearness in the theological speculations of Swedenborg and the philosophical speculations of Kant. All these we pass over with bare mention, because these thinkers approached the subject from the philosophic rather than the scientific side—in the metaphysical rather than the scientific spirit.

The first serious attempt at scientific presentation of the subject was by the celebrated naturalist, Lamarck, in a work entitled "Philosophic Zoölogique," published in 1809. It is not necessary, in this rapid sketch, to give a full account of Lamarck's views. Suffice it to say that the essential idea of evolution, viz., the indefinite variability and the derivative origin of species, was insisted on with great learning and skill, and illustrated by many examples. With Lamarck, the factors of evolution or causes of change of organic forms were—1. Modification of organs in function and therefore in structure, by a

  1. From advance sheets of Professor Le Conte's work on "Evolution and its Relation to Religious Thought," in preparation by D. Appleton & Co.