I'874-] INSECTIVOROUS PLANTS. 325 



just like the helix of a human ear, if you were to stuff flies 

 within the fold. 



Yours most sincerely, 



CH. DARWIN. 



C. Darwin to Asa Gray. 



Down, June 3 [1874]. 



.... I am now hard at work getting my book on Drosera 

 & Co. ready for the printers, but it will take some time, for I 

 am always finding out new points to observe. I think you 

 will be interested by my observations on the digestive process 

 in Drosera ; the secretion contains an acid of the acetic series, 

 and some ferment closely analogous to, but not identical 

 with, pepsine ; for I have been making a long series of 

 comparative trials. No human being will believe what I 

 shall publish about the smallness of the doses of phosphate 

 of ammonia which act. 



.... I began reading the Madagascar squib * quite gravely, 

 and when I found it stated that Felis and Bos inhabited 

 Madagascar, I thought it was a false story, and did not 

 perceive it was a hoax till I came to the woman. . . . 



C. Darwin to F. C. Donders.\ 



Down, July 7, 1874. 



MY DEAR PROFESSOR DONDERS, My son George writes 

 to me that he has seen you, and that you have been very kind 

 to him, for which I return to you my cordial thanks. He 

 tells me on your authority, of a fact which interests me in 

 the highest degree, and which I much wish to be allowed to 

 quote. It relates to the action of one millionth of a grain of 

 atropine on the eye. Now will you be so kind, whenever you 

 can find a little leisure, to tell me whether you yourself have 



* A description of a carnivo- f Professor Donders, the well- 

 rous plant supposed to subsist on known physiologist of Utrecht, 

 human beings. 



