1877 MR. F. DARWIN ON DROSERA 59 



the fed side the leaves are much larger, differently 

 coloured, and more numerous flower stalks taller 

 and more numerous, and, I believe, far more seed- 

 capsules, but these not yet counted. It is particu- 

 larly interesting that the leaves fed on meat contain 

 very many more starch granules (no doubt owing to 

 more protoplasm being first formed), so that sections 

 stained with iodine of fed and unfed leaves are to 

 the naked eye of very different colour. 



There, I have boasted to my heart's content ; and 

 do you do the same, and tell me what you have been 

 doing. 



Yours very sincerely, 



CH. DABWIN. 



From G. J. Romanes. 



Dunskaith, Ross-shire : August 11, 1877. 



I was very pleased to get your long and genial 

 letter, which I will answer seriatim. 



The ' muslin ' in the hypothetical plexus seems to 

 be very coarse in some specimens and finer in others 

 the young and active individuals enduring severer 

 forms of section than the old. And in exploring by 

 graduated stimuli, areas of different degrees of excita- 

 bility may be mapped out, and these areas are pretty 

 large, averaging about the size of one's finger-nails. 

 I am rather inclined to think that these areas are 

 determined by the course of well-differentiated nerve- 

 tracts, while the less-differentiated ones are probably 

 more like muslin in their mesh. But the only reason 

 why I resort to the supposition of nerve-tracts at all 

 is because of the sudden blocking of contractile waves 



