Page:Popular Science Monthly Volume 37.djvu/526

510 than the varying attitudes of the naturalist toward those local modifications of species called geographical variations.

It was early noticed that, while individuals of any one species in any limited region are substantially alike, this perfect identity disappears with the examination of wider extent of territory. These differences were often too small to justify the formation or recognition of a new species, but too evident to be wholly neglected. These subordinate species were termed by Linnæus varieties, and their geographical basis was often recognized. Thus, of his Homo sapiens, or aboriginal man, Linnæus recognized four varieties—asiaticus, americanus, afer, and europæus. As with the varieties of man, so with those of other animals and plants. The individuals of England were not quite those of the same species in Italy, and those in America showed their own peculiarities.

Sometimes these qualities could be exactly measured, in which case a new species was described. Sometimes they proved elusive, and the supposed new species were added to the great dust-heap of synonymy. The work of the systematic zoölogists of the last generation was chiefly in museum cataloguing and labeling. To them these half-tangible varieties were the object of special opprobrium. On the museum shelves they were simply a nuisance, obscuring the characters of the real species and throwing closetformed ideas of nature into utter confusion. Prof. Cope tells us how variant shells have been crushed under the heel of the indignant conchologist, because they would go neither into species A "nor species" B. "Specimens were often preserved from typical localities," so that no confusion might be introduced among the cherished specific characters. That Nature went on producing these varying and intermediate forms was no concern of the zoologist. That such forms were any part of Nature's plan apparently never occurred to the followers of Linnæus.

Says the botanist De Candolle: "They are mistaken who suppose that the greater part of our species are clearly limited, and that the doubtful species are in a feeble minority. This seemed to be true so long as a genus was imperfectly known, and its species were founded on few specimens—that is to say, were provisional only; just as we come to know them better, intermediate forms flow in, and doubts as to the limits of the species become more numerous."

The ease with which slight variations have deceived and confused naturalists is one of the most discouraging features in the history of science. Such variations have formed the basis of thousands of useless and distracting names.

When Darwin was at work upon his monograph of the barnacles, he wrote to a friend:

"Systematic work would be easy were it not for this