492 CLIMBING AND INSECTIVOROUS PLANTS. [i860. 



prising part seems to me that the effect should be visible, 

 and not under very high power ; for after trying a high pow- 

 er, I thought it would be safer not to consider any effect 

 which was not plainly visible under a two-thirds object glass 

 and middle eye-piece. The effect which the carbonate of 

 ammonia produces is the segregation of the homogeneous 

 fluid in the cells into a cloud of granules and colourless fluid ; 

 and subsequently the granules coalesce into larger masses, 

 and for hours have the oddest movements — coalescing, divid- 

 ing, coalescing ad infinitum. I do not know whether you will 

 care for these ill-written details ; but, as you asked, I am 

 sure I am bound to comply, after all the very kind and great 

 trouble which you have taken." 



On his return home he wrote to Sir J. D. Hooker (No- 

 vember 21, i860) : — 



"I have been working like a madman at Drosera. Here 

 is a fact for you which is certain as you stand where you are, 

 though you won't believe it, that a bit of hair -^s iwo °f one 

 grain in weight placed on gland, will cause one of the gland- 

 bearing hairs of Drosera to curve inwards, and will alter the 

 condition of the contents of every cell in the foot-stalk of 

 the gland." 



And a few days later to Lyell : — 



" I will and must finish my Drosera MS., which will take 

 me a week, for, at the present moment, I care more about 

 Drosera than the origin of all the species in the world. But 

 I will not publish on Drosera till next year, for I am fright- 

 ened and astounded at my results. I declare it is a certain 

 fact, that one organ is so sensitive to touch, that a weight 

 seventy-eight times less than that, viz., y-oVo of a g ram > which 

 will move the best chemical balance, suffices to cause a con- 

 spicuous movement. Is it not curious that a plant should be 

 far more sensitive to the touch than any nerve in the human 

 body ? Yet I am perfectly sure that this is true. When I 

 am on my hobby-horse, I never can resist telling my friends 

 how well my hobby goes, so you must forgive the rider." 



The -work was continued, as a holiday task, at Bourne- 



