Jhgiiiiiings of Natural History in America. 387 



Jefferson declarCvS that Clayton was a native Virginian, and such is the 

 confusion in the records that it is quite possible that such may be the 

 fact.' 



Still another pioneer was Doctor John Mitchell, born in England about 

 1680, and settled early in the last century at Urbana, Virginia, ontheRap- 

 pahatniock, where he remained nearly fifty years, practicing medicine and 

 promoting science. He appears to have been a man of genius and broad cul- 

 ture, and was one of the earliest chemists and physicists in America. His 

 political and botanical waitings were well received, and his map of North 

 America is still an authority in l:)oundary matters. He was a correspondent 

 of Linnaeus, and in 1 740 sent Collinson a paper in which thirty new genera 

 of Virginia plants were proposed.^ His Dissertation upon the Elements 

 of Botany and Zoology^ was dated Virginia, 1738, and was thus almost 

 contemporary with the first edition of the Systema Naturae of Einnseus, 

 though it was not printed until ten years after it was written. This was 

 the first work upon the principles of science ever written in America. 

 In 1 743 he connnunicated to the Royal Society An Essay upon the Causes 

 of the different Colours of People in different Climates,'* writing from the 

 standpoint of an evolutionist. He also communicated An Account of the 

 Preparation and Uses of the various Kinds of Potash, ^and a Eetter 

 concerning the Force of electrical Cohesion.* His fame rests chiefly, 

 however, upon his investigations into the yellow fever epidemic of 1737- 

 1742, published after his death by his friends, Franklin and Rush,' In 

 1743 he appears to have been engaged in physiological researches upon 

 the opossum, which, however, were never published. In 1746 Doctor 

 Mitchell returned to England, and upon the voj^age was captured by 

 French or Spanish pirates, and his collections and apparently his manu- 

 scripts destroyed. He became a Fellow of the Royal Society, and in 

 1748 was writing a work upon the natural and medical history of North 

 America.*^ He died at an advanced age, about 1772. His name is per- 

 petuated in that of our beautiful little partridge berry, Mitchella rcpcns. 

 "Mitchell and Clayton together," says Tuckerman, "gave to the botany 

 of Virginia a distinguished luster." 



Doctor John Tennent, of Port Royal, Virginia, seems to have been a 

 man of botanical tastes. He it was who brought into view the virtues 

 of the Seneca snake root, publishing at Williamsburg, in 1736, an essay 



'Spotswood Letters, I, pp. i, 8; II, pp. 44, 58, 354. 



== Darlington, Memorials of John Bartram and Humphrey Marshall, p. 21. 



3 Dissertatio brevis de Principiis Botanicorum et Zoologorum, deque novo stabil- 

 iendo naturae rerum congruo cum Appendice aliquot generum plantarum recens con- 

 ditorum et in Virginia observatorum. Nuremburg, 1748. 



■* Philosophical Transactions, Xlylll, 1744, p. 102. 



sidem.,XIvV, 1748, p. 541. 



*Idem., LI, Pt. i, 1759, p. 390. 



^ American Medical and Philosophical Register, IV. 



^ James Edward Smith, Correspondence of Linnaeus, II, pp. 442-451. 



