286 EVOLUTION [CHAP. IV 



Letter 207 To J. D. Hooker. 



Down, Jan. 6th [1868]. 



Many thanks about names of plants, synonyms, and male 

 flowers all that I wanted. 



I have been glad to see Watson's letter, and am sorry he 

 is a renegade about Natural Selection. It is, as you say, 

 characteristic, with the final fling at you. 



His difficulty about the difference between the two genera 

 of St. Helena Umbellifers is exactly the same as what Nageli 

 has urged in an able pamphlet, 1 and who in consequence 

 maintains that there is some unknown innate tendency to 

 progression in all organisms. I said in a letter to him that 

 of course I could not in the least explain such cases ; but 

 that they did not seem to me of overwhelming force, as long 

 as we are quite ignorant of the meaning of such structures, 

 whether they are of any service to the plants, or inevitable 

 consequences of modifications in other parts. 



I cannot understand what Watson means by the " counter- 

 balance in nature ' to divergent variation. There is the 

 counterbalance of crossing, of which my present work daily 

 leads me to see more and more the efficiency ; but I suppose 

 he means something very different. Further, I believe varia- 

 tion to be divergent solely because diversified forms can best 

 subsist. But you will think me a bore. 



I enclose half a letter from F. Miiller (which please return) 

 for the chance of your liking to see it ; though I have doubted 

 much about sending it, as you are so overworked. I imagine 

 the Solanuiti-\\\ie flower is curious. 



I heard yesterday to my joy that Dr. Hildebrand has been 

 experimenting on the direct action of pollen on the mother- 

 plant with success. He has also succeeded in making a true 

 graft-hybrid between two varieties of potatoes, in which I 

 failed. I look at this as splendid for pan genesis, as being 

 strong evidence that bud-reproduction and seminal repro- 

 duction do not essentially differ. 



My book is horribly delayed, owing to the accursed 

 index-maker. 2 I have almost forgotten it ! 



1 "Ueber Entstehung und Begriff der naturhist. Art." Sitz. der K. 

 Bayer. Akad. der Wiss. zu Munchen, 1865. Some of Nageli's points 

 are discussed in the Origin, Ed. v., p. 151. 



2 Darwin thoroughly appreciated the good work put into the index of 

 The Variation of Animals and Pla?its, 



