358 THE BCIENTIFIC MONTHLY
tion adopted by different writers on Natural History. In his rather complete reply to the doctor written from Monticello, February 22, 1814, Jefferson approaches the problem in its broadest possible aspect I quote here only in part.
. . . The text of this answer wiU be found in an obserration in jonr letter, when, speaking of the nosological systems, jou saj that disease has been found to be an unit. Nature, has, in truth, produced units only through all her works. Classes, orders, genera, species are not of her work. Her creation is of indi- viduals. No two animals are exactly alike; no two plants, nor even two leaves or blades of grass; no two crystallizations. . . . This infinitude of units or in- dividuals are far beyond the capacity of our memory. We are obliged, in aid of that, to distribute them into masses, throwing into each of these all indi- viduals which have a certain degree of resemblance; to subdivide these again into smaller groups, according to certain points of dissimilitude observable in them, and eo on until we have formed what we call a series of classes, orders, genera and species. In doing this we arbitrarily fix on such characteristic re- semblances and differences as seem to us most prominent and invariable in the several subjects, and most likely to take a strong hold in our memories. Thus Bay formed one classification on such lines of division as struck him most favorable; Klein adopted another; Brisson a third, and other naturalists other designations, till Linnsus appeared. Fortunately for science, he conceived in the three kingdoms of nature, modes of classification which obtained the appro- bation of the learned of all nations. His system was accordingly adopted by aU, and united all in a general language. . . . This classification was indeed liable to the imperfection of bringing into the same group individuals which, though resembling in the characteristics adopted by the author for his classifi- cation, yet have strong marks of dissimilitude in other respects. But to this objection every mode of classification must be liable. . . . Nature has not ar- ranged her productions on a single and direct line. They branch at every step, and in every direction, and he who attempts to reduce them into depart- ments, is left to do it by the lines of his own fancy. . . . But neither is this so important a consideration as that of uniting aU nations under one language in Natural History. . . . Linnfleus' method was received, understood and conven* tionally settled among the learned, and was even getting into common use. To disturb it then was unfortunate. The new system attempted in botany by Jussieu ... is subject to the same regret. ... I adhere to the Linnsan (sys- tem) because it is suflcient as a ground-work, admits of supplementary inser- tions as new productions are discovered, and mainly because it has got into so general use that it wiU not be easy to displace it, and still less to find another which shall have the same singular fortune of obtaining the general consent. . . . I am not myself apt to be alarmed at innovations recommended by reason. That' dread belongs to those whose interests or prejudices shrink from the ad- vance of truth and science. My reluctance is to give up an universal language of which we are in possession, without an insurance of general consent to receive
another.
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There would seem to be little encouragement here for a bibliographic botanist with his new combinations and resurrected ghost species ; and as little for the man who regards a proposed new species as a piece of property belonging to him by moral right. The greatest service to the greatest number was the test to which Jefferson brought all things.
We must now pass to the consideration of another phase of Jeffer- son's influence on botany, that exerted in the academic sphere. And
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