Xii HISTORICAL SKETCH. 



give any idea of his views would be superfluous on my 

 part. 



Mr. Herbert Spencer, in an essay (originally published in 

 the "Leader," March, 1852, and republished in his "Essays," 

 in 1858), has contrasted the theories of the Creation and the 

 Development of organic beings with remarkable skill and 

 force. He argues from the analogy of domestic productions, 

 from the changes which the embryos of many species un- 

 dergo, from the difficulty of distinguishing species and varie- 

 ties, and from the principle of general gradation, that species 

 have been modified; and he attributes the modification to 

 the change of circumstances. The author (1855) has also 

 treated Psychology on the principle of the necessary acquire- 

 ment of each mental power and capacity by gradation. 



In 1852 M. Naudin, a distinguished botanist, expressly 

 stated, in an admirable paper on the Origin of Species 

 (" Revue Horticole," p. 102 ; since partly republished in the 

 "Nouvelles Archives du Museum," torn. i. p. 171), his belief 

 that species are formed in an analogous manner as varieties 

 are under cultivation ; and the latter process he attributes to 

 man's power of selection. But he does not show how selec- 

 tion acts under nature. He believes, like Dean Herbert, 

 that species, when nascent, were more plastic than at 

 present. He lays weight on what he calls the principle of 

 finality, " puissance mysterieuse, indeterminee ; fatalite pour 

 les uns ; pour les autres volonte providentielle, dont Faction 

 incessante sur les etres vivantes determine, a toutes les 

 epoques cle l'existence du nionde, la forme, le volume, et la 

 duree de chacun d'eux, en raison de sa destinee dans l'ordre 

 de choses dont il fait partie. C'est cette puissance qui har- 

 monise chaque membre a l'ensemble, en l'appropriant a la 

 fonction qu'il doit remplir dans l'organisme generale de la 

 nature, fonction qui est pour lui sa raison d'etre." * 



* From references in Bronn's " Untersuchungen iiber die Entwickel- 

 ungs-Gesetze," it appears that the celebrated botanist and palaeontolo- 

 gist Unger published, in 1852, his belief that species undergo development 

 and modification. Dalton, likewise, in Pander and Dalton's work on 

 Fossil Sloths, expressed, in 1821, 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 l'Espece," 

 it seems that Bory St. Vincent, Burdach, Poiret, and Fries have all 

 admitted that new species are continually 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 sepa- 

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

 natural history or geology, 



