358 EVOLUTION [CHAP. V 



Letter 268 I am very much obliged for your photograph, which I 

 am particularly glad to possess, and I send mine in return. 



I see you allude to Hilgendorf's statements, which I 

 was sorry to see disputed by some good German observer. 

 Mr. Hyatt, an excellent palaeontologist of the United 

 States, visited the place, and likewise assured me that 

 Hilgendorf was quite mistaken. 1 



I am grieved to hear that your eyesight still continues 

 bad, but anyhow it has forced your excellent work in your 

 last essay. 



May 4th. Here is what Mr. Weir says : 



" In reply to your inquiry of Saturday, I regret that 

 I have little to add to my two communications to the 

 Entomological Society Transactions. 



" I repeated the experiments with gaudy caterpillars for 

 years, and always with the same results : not on a single 

 occasion did I find richly coloured, conspicuous larvae 

 eaten by birds. It was more remarkable to observe that 

 the birds paid not the slightest attention to gaudy caterpillars, 

 not even when in motion, the experiments so thoroughly 

 satisfied my mind that I have now given up making them." 



Letter 269 To Lawson Tait. 



The late Mr. Lawson Tait wrote to Mr. Darwin (June 2nd, 1875) : 

 " I am watching a lot of my mice from whom I removed the tails 

 at birth, and I am coming to the conclusion that the essential use 

 of the tail there is as a recording organ that is, they record in their 

 memories the corners they turn and the height of the holes they 

 pass through by touching them with their tails." Mr. Darwin was 

 interested in the idea because " some German sneered at Natural 



Selection and instanced the tails of mice." 



June iitb, 1875. 



It has just occurred to me to look at the Origin of 

 Species (Ed. VI., p. 170), and it is certain that Bronn, 

 in the appended chapter to his translation of my book 

 into germ an, did advance ears and tail of various species 

 of mice as a difficulty opposed to Natural Selection. I 

 answered with respect to ears by alluding to Schobl's 

 curious paper (I forget when published) 2 on the hairs of 



1 See Letters 252-7. 



2 J. Schobl, "Das aiissere Ohr der Mause als wichtiges Tastorgan." 

 Archiv. Mik. Anat.^ VII., 1871, p. 260. 



