268 BOTANY [CHAP. X 



Letter 598 To E. Cresy. 



Down, Dec. I2th [1860?]. 



After writing out the greater part of my paper on Drosera, 

 I thought of so many points to try, and I wished to re-test 

 the basis of one large set of experiments, namely, to feel still 

 more sure than I am, that a drop of plain water never produces 

 any effect, that I have resolved to publish nothing this year. 

 For I found in the record of my daily experiments one sus- 

 picious case. I must wait till next summer. It will be difficult 

 to try any solid substances containing nitrogen, such as ivory ; 

 for two quite distinct causes excite the movement, namely, 

 mechanical irritation and presence of nitrogen. When a solid 

 substance is placed on leaf it becomes clasped, but is released 

 sooner than when a nitrogenous solid is clasped ; yet it is 

 difficult (except with raw meat and flies) to be sure of the 

 result, owing to differences in vigour of different plants. The 

 last experiments which I tried before my plants became too 

 languid are very curious, and were tried by putting micro- 

 scopical atoms on the gland itself of single hairs ; and it is 

 perfectly evident that an atom of human hair, yg-J-o-^ of a grain 

 (as ascertained by weighing a length of hair) in weight, causes 

 conspicuous movement. I do not believe (for atoms of cotton 

 thread acted) it is the chemical nature ; and some reasons 

 make me doubt whether it is actual weight ; it is not the 

 shadow ; and I am at present, after many experiments, con- 

 founded to know what the cause is. That these atoms did 

 really act and alter the state of the contents of all the cells 

 in the glandular hair, which moved, was perfectly clear. But 

 I hope next summer to make out a good deal more . . . 



Letter 599 To J. D. Hooker. 



Down, May I4th [1861], 



I have been putting off writing from day to day, as I did 

 not wish to trouble you, till my wish for a little news will not 

 let me rest . . . 



I have no news to tell you, for I have had no interesting 

 letters for some time, and have not seen a soul. I have been 

 going through the Cottage Gardener of last year, on account 

 chiefly of Beaton's 1 articles ; he strikes me as a clever but 



1 Donald Beaton (1802-63). Biographical notices in the J r our?ial oj 

 Horticulture and the Cottage Gardener, XIII., p. 153, zn&Jottrn. Hort., 

 1863, pp. 349 and 415, are referred to in Britten & Boulger's Biographical 



