THE BOTANISTS OF PHILADELPHIA. 5 



along systematic lines. It was not until after the perfecting 

 of the microscope and the epoch-making period, beginning 

 with issue of Darwin's Origin of Species, that the modern 

 study of botany may be said to have Ijegun in Phila- 

 delphia. The pursuance of botany in Philadelphia and in 

 America generally can be divided into four periods : 



(1) The early descriptions of the flora by persons not con- 

 versant with botany, who described the plants after the man- 

 ner of the old herbalists, chiefly as interesting rarities, or as 

 useful, natural medicines. The sect of German Pietists 

 presided over by Kelpius, established in 1694 on the lower 

 Wissahickon, a garden where medicinal plants were raised 

 for use and study. It may, therefore, be styled the first 

 garden in America where a botannical arrangement of 

 plants was made.* In 1739 was published at Ley den, 

 in Holland, an essay in Latin, entitled, " Experimenta et 

 Meletemata de Plantarum generatione," by the learned 

 Governor of Pennsylvania, James Logan. It was after- 

 wards, in 1747, republished in London, with an English 

 translation, by Dr. John Fothergill. The experiments and 

 observations were admirably illustrative of the doctrine of 

 sexes of plants t established by Jacob Camerarius. This 

 may be said to be the first work of any botanical import- 

 ance issued by a Philadelphia botanist. Many of Logan's 

 ideas smack of medieval scolasticism, so that he is properly 

 placed in the Pre-Linncean period. 



(2) The period of the ascendency of Linna3an ideas. 

 John Bartram was one of the first persons who may be said 



*Sachse. The Oer^nan Pietists of Pennsylvania, p. 75. 



t See an article of mine, "James Logan," Botanical Gazette, Aug., 1894. 



18S9. Sack's Histori/ of Botany, 891-092. 



LS49. Darlington— il/e/Ho?-/a;s of Bartram ct Marshall, 21. 



