XiT HISTORICAL SKETCH, 



forms. ** Thus living plants and animals are not sepa- 

 rated from the extinct by new creations, but are to be 

 regarded as their descendants through continued repro- 

 duction/' 



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 

 Tespece, nous conduisent directement aux idees emises 

 par deux hommes justement celebres, Geoffroy Saint- 

 Hilaire et Goethe." Some other passages scattered through 

 M. TiCcoq^s large work make it a little doubtful how far he 

 extends his views on the modification of species. 



The "Philosophy of Creation '' has been treated in a 

 m-: ^terly manner by the Rev. Baden Powell, in his "Essays 

 on the Unity of Worlds," 1855. Nothing can be more 

 striking than the manner in which he shovv^s that the intro- 

 duction of new species is "a regular, not a casual phenom- 

 enon," or, as Sir John Herschel expresses it, "a natural 

 in contradistinction to a miraculous process." 



The third volume of the "Journal of the Linnean 

 Society " contains papers, read July 1, 1858, by Mr. 

 Wallace and myself, in which, as stated in the introductory 

 remarks to this volume, the theory of Natural Selection is 

 promulgated by Mr. Wallace with admirable force and 

 clearness. 



Von Baer, toward whom all zoologists feel so profound a 

 respect, expressed about the year 1859 (see Prof. Rudolph 

 Wagner, " Zoologisch-Anthropologische Untersuchungen," 

 1861, s. 51) his conviction, chiefly grounded on the laws of 

 geographical distribution, that forms now perfectly distinct 

 have descended from a single parent-form. 



In June, 1859, Professor Huxley gave a lecture before 

 the Royal Institution on the " Persistent Types of Animal 

 Life." Referring to such cases, he remarks, " It is difficult 

 to comprehend the meaning of such facts as these, if we 

 suppose that each species of animal and plant, or each 

 great type of organization, was formed and placed upon the 

 surface of the globe at long intervals by a distinct act of 

 creative power; and it is well to recollect that such an 

 assumption is as unsupported by tradition or revelation as 

 it is opposed to the general analogy of nature. If^ on the 

 other hand, we view *"' Persistent Types" in r^ation to 



