106 THE UNFINISHED BOOK. [1857. 



I am in no hurry for a few weeks. Will you turn this in 

 your head, when, if ever, you have leisure ? The subject is 

 very important for my work, though I clearly see many causes 

 of error. . 



C. Darwin to Asa Gray. 



Down, Feb. 2ist [1859]. 



MY DEAR GRAY, My last letter begged no favour, this 

 one does : but it will really cost you very little trouble to 

 answer me, and it will be of very great service to me, 

 owing to a remark made to me by Hooker, which I cannot 

 credit, and which was suggested to him by one of my letters. 

 He suggested my asking you, and I told him I would not 

 give the least hint what he thought. I generally believe 

 Hooker implicitly, but he is sometimes, I think, and he 

 confesses it, rather over-critical, and his ingenuity in discover- 

 ing flaws seems to me admirable. Here is my question : 

 "Do you think that good botanists in drawing up a local 

 Flora, whether small or large, or in making a Prodromus like 

 De Candolle's, would almost universally, but unintentionally 

 and unconsciously, tend to recprd (i.e. marking with Greek 

 letters and giving short characters) varieties in the large or 

 in the small genera ? Or would the tendency be to record the 

 varieties about equally in genera of all sizes ? Are you your- 

 self conscious on reflection that you have attended to, and 

 recorded more carefully the varieties in large or small, or very 

 small genera ? " 



I know what fleeting and trifling things varieties very often 

 are ; but my query applies to such as have been thought 

 worth marking and recording. If you could screw time to 

 send me ever so brief an answer to this, pretty soon, it would 

 be a great service to me. 



Yours most truly obliged, 



CH. DARWIN. 



