AGASSIZ AND EVOLUTION. 17 



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 produc- 

 tion and supply, and not by any changes in the relative values of gold 

 and silver ; and further, that if every measure for extending the mone- 

 tary 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 agri- 

 culturists in the sale of wheat in the world's markets. 



AGASSIZ AND EYOLUTIOX. * 



By Peofessob JOSEPH LE CONTE. 



IN order to clear np the conception of evolution, it is necessary to 

 give a brief history of the idea, and especially to explain the rela- 

 tion 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 phi- 

 losophy. 



Like all great ideas, we find the first germs of this in Greek phi- 

 losophy, 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 Rerum 

 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 " Philo- 

 sophic Zoologique," 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 learn- 

 ing 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 



rude ; they have very little machinery. The system might be greatly improved, and the 

 produce thereby increased." — Third Report on the Depression of Trade, pp. 82, S3. 



* From advance sheets of Professor Le Conte's work on " Evolution and its Relation to 

 Religious Thought," in preparation by D. Appleton & Co. 

 vol,. XXXII. — 2 



