Page:Popular Science Monthly Volume 71.djvu/127

THE PLACE OF LINNÆUS IN THE UNFOLDING OF SCIENCE; HIS VIEWS ON THE CLASS MAMMALIA^[1]

By WILLIAM K. GREGORY

COLUMBIA UNIVERSITY AND THE AMERICAN MUSEUM OF NATURAL HISTORY

IN order rightly to appraise the value of Karl von Linné's contributions to biological science, it is necessary to bear in mind two very axiomatic facts. Our first axiom is that Linnæus became a point of departure in the history of modern biology only because he was in turn the product of the intersection of a great number of important causal series, which ramify and intertwine indefinitely and stretch back into the remote past of every aspect of life. The second axiom is that every new idea, or, for that matter, every new event, is the fertile hybrid from the fortuitous crossing of two or more specifically distinct old ideas, or events. And in order that we may discern a few of these fortuitous crossings and follow a little some of these interminable and intricate streams of cause and effect, it may not be inappropriate, in connection with the two-hundredth anniversary of the birth of Linnæus, to touch briefly upon a series of seven epochs of thought, from Aristotle to Darwin; and further to glance at the principles and facts upon which Linnæus based his two great contributions to the broader knowledge of the class of which man is the dominating member.

Not to go back indefinitely, we begin with the Aristotelian or initial analytic epoch of the fourth century b. c. Aristotle's theory of the genetic relationship of the chain of beings from polyp to man did not, of course, materially influence Linnæus. The idea of evolution which St. Thomas Aquinas, the "princeps scholasticorum" understood and developed, was not destined to come to its fruition through the schoolmen or even in Linnæus or Cuvier. But the true relation of Aristotle's thought to that of Ray and Linnæus may be exhibited in the following well-known citations from "The Parts of Animals."^[2]

Some animals are viviparous, some oviparous, some vermiparous. The viviparous are such as man, and the horse, and all those animals which have hair; and of the aquatic animals, the whale kind, as the dolphin and cartilag-

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1. This article is here published by courtesy of the council of the New York Academy of Sciences. It is largely adapted from a forthcoming memoir by the writer on the "History of the Classification of the Mammalia," prepared under the direction of Professor Henry Fairfield Osborn.
2. Quoted by W. Whewell, "History of the Inductive Sciences," 8vo, London, 1837, Vol. III., pp. 347.