110 A CENTUEY OF SCIENCE 



both men are proving evolution, but consciously they 

 are firm creationists. It is astonishing that with their 

 extended and minute knowledge of living organisms and 

 their philosophic type of mind neither could see the true 

 significance of the imperceptible transitions between 

 some species, which if they do not actually pass into, at 

 least shade towards, one another. 



Dana speaks of "the endless diversities in individu- 

 als ' ' that compose a species, and then states that a living 

 species, like an inorganic one, "is based on a specific 

 amount or condition of concentered force defined in the 

 act or law of creation." Species, he says, are perma- 

 nent, and hybrids "cannot seriously trifle with the true 

 units of nature, and at the best, can only make tempo- 

 rary variations. " "We have therefore reason to believe 

 from man's fertile intermixture, that he is one in species : 

 and that all organic species are divine appointments 

 which cannot be obliterated, unless by annihilating the 

 individuals representing the species." 



Through the activities of the French the world was 

 prepared for the reception of evolution, and now it was 

 already in the minds of many advanced thinkers. In 

 1860 Asa Gray sent to the editor of the Journal (29, 1) 

 an article by the English botanist, Joseph D. Hooker, 

 entitled "On the Origination and Distribution of 

 Species," with these significant remarks: 



''The essay cannot fail to attract the immediate and profound 

 attention of scientific men ... It has for some time been 

 manifest that a re-statement of the Lamarckian hypothesis is 

 at hand. We have this, in an improved and truly scientific 

 form, in the theories which, recently propounded by Mr. Dar- 

 win, followed by Mr. Wallace, are here so ably and altogether 

 independently maintained. When these views are fully laid 

 before them, the naturalists of this country will be able to 

 take part in the interesting discussion which they will not fail 

 to call forth." 



Hooker took up a study of the flora of Tasmania, of 

 which the above cited article is but a chapter, with a 

 view to trying out Darwin's theory, and he now accepts 

 it. He says, "Species are derivative and mutable." 

 "The limits of the majority of species are so undefina- 

 ble that few naturalists are agreed upon them." 



