394 BOTANY [CHAP. XI 



Letter 715 other stamens. The cohering stamens to the right and left 

 of the single one seem to me to be pushed out a little laterally. 

 When you have finished your observations, you really ought 

 to send an account with a diagram to Nature^ recalling your 

 generalisation about the diadelphous structure, and now ex- 

 plaining the exception of Coronillal 



Do add a remark how almost every detail of structure has 

 a meaning where a flower is well examined. 



Your observations pleased me so much that I could not 

 sit still. for half an hour. 



Please to thank Mr. Payne 2 for his remarks, which are of 

 value to me, with reference to Mimosa. I am very much in 

 doubt whether opening the sashes can act by favouring the 

 evaporation of the drops ; may not the movement of the leaves 

 shake off the drops, or change their places? If Mr. Payne 

 remembers any plant which is easily injured by drops, I wish 

 he would put a drop or two on a leaf on a bright day, and cover 

 the plant with a clean bell-glass, and do the same for another 

 plant, but without a bell-glass over it, and observe the effects. 



Thank you much for wishing to see us again at Abinger, 

 and it is very doubtful whether it will be Coronilla^ Mr. Payne, 

 the new garden, the children, E. [Lady Farrer], or yourself 

 which will give me the most pleasure to see again. 



P.S. i. It will be curious to note in how many years the 

 rough ground becomes quite uniform in its flora. 



P.S. 2. One may feel sure that periodically nectar was 

 secreted within the flower and then secreted by the calyx, as 

 in some species of Iris and orchids. This latter being taken 

 advantage of in Coronilla would allow of the secretion within 

 the flower ceasing, and as this change was going on in the two 

 secretions, all the parts of the flower would become modified 

 and correlated. 



Letter 716 To J. Burdon Sanderson. 



Down, Tuesday. Sept. Qth [1873]. 



Sir J. Burdon Sanderson showed that in Dioncea movement is accom- 

 panied by electric disturbances closely analogous to those occurring in 

 muscle (see Nature, 1874, pp. 105, 127; Proc. R. Soc., XXI., and Phil. 

 Trans., Vol. CLXXIII., 1883, where the results are finally discussed). 



1 The observations were published in Nature, Vol. X., 1874, p. 169. 

 Lord Farrer's gardener. 



