HISTORICAL SKETCH 17 



"puissance mysterieuse, indeterminee ; fatalite pour Ics uns ; 

 pour les autres, volonte providentielle, dont Taction inces- 

 sante sur les etres vivants determine, a toutes les epoques de 

 I'existence du monde, la forme, le volume, et la duree de 

 chacun d'eux, en raison de sa destinee dans I'orde de choses 

 dont il fait partie. C'est cette puissance qui harmonise 

 chaque membre a I'ensemble, en I'appropriant a la fonction 

 qu'il doit remplir dans I'organisme general de la nature, fonc- 

 tion qui est pour lui sa raison d'etre."* 



In 1853 a celebrated geologist, Count Keyserling ('Bulletin 

 de la Soc. .Geolog./ 2nd Sen, torn. x. p. 357), suggested that 

 as new diseases, supposed to have been caused by some 

 miasma, have arisen and spread over the world, so at certain 

 periods the germs of existing species may have been chem- 

 ically afifected by circumambient molecules of a particular 

 nature, and thus have given rise to new forms. 



In this same year, 1853, Dr. Schaaffhausen published an 

 excellent pamphlet ('Verhand. des Naturhist. Vereins der 

 Preuss. Rheinlands,' &c.), in which he maintains the devel- 

 opment of organic forms on the earth. He infers that many 

 species have kept true for long periods, whereas a few have 

 become modified. The distinction of species he explains by 

 the destruction of intermediate graduated forms. "Thus 

 living plants and animals are not separated from the extinct 

 by new creations, but are to be regarded as their descendants 

 through continued reproduction." 



A well-known French botanist, M. Lecoq, writes in 1854 

 ('Etudes sur Geograph. Bot.,' torn. i. p. 250), "On voit que 

 nos recherches sur la fixite ou la variation de I'espece, nous 

 conduisent directement aux idees emises, par deux hommes 

 justement celebres, Geoffroy Saint-Hilaire et Goethe." Some 



* From references in Bronn's ' Untersuchungen iiber die Entwickclungs- 

 Gesetze,' it appears that the celebrated botanist and palxontologist Unger 

 published, in 1852, his belief that species undergo development and modifi- 

 cation. Dalton, likewise, in Pander and Dalton's work on Fossil Sloths, ex- 

 pressed, in 1 82 1, a similar belief. Similar views have, as is well known, 

 been maintained by Oken in his mystical ' Natur-Philosophie.' From other 

 references in Godron's work ' Sur I'Espece,' it seems that Bory St. Vincent, 

 Burdach, Poiret, and Fries, have all admitted that new species arc con- 

 tinually being produced. 



I may add, that of the thirty-four authors named in this Historical Sketch, 

 who believe in the modification of species, or at least disbelieve in separate 

 acts of creation, twenty-seven have written on special branches of natural 

 history or geology. 



