84 LETTER XXXIII. 



of the Sun-dew leaf, no fewer than two thousand little 

 digesting cells, or stomachs, are incessantly exercising 

 and combining their tiny forces ! 



There is still the ruby-coloured point to examine. 

 In its interior structure it is like the hair itself, only 

 all the parts are more solid ; it is here that the fluid 

 secreted by the hair is finally concentrated ; and it is 

 fi*om this that the dew is continually exuding, so as to 

 stand upon it like a drop of water. The water has a 

 slightly acrid taste, and is probably thrown off from 

 the leaf, because its continued presence in the system 

 of the Sun-dew would be pernicious. 



The hairs of our British Droseras possess the 

 power of closing upon insects and holding them fast. 

 " When an insect settles upon them, it is retained by 

 the viscosity of the glands, and in a little while the 

 hairs exhibit a considerable degree of irritability by 

 curving inwards, and thus holding it secure." — (Hen- 

 slow.) And Dr. Royle describes the phenomenon as 

 occurring so obviously in an Indian species of Sun-dew, 

 that he had called it " the fly-catching" in consequence. 



The description just given of the hairs of the Sun-dew, 

 is in part applicable to all other hairs ; for they are 

 generally constructed upon a similar plan, and are 

 often, when filled with moisture, most beautiful and 

 elaborately constructed organs. Botanists distinguish 

 two principal sorts of hairs ; the glandular, in which 

 the hair is either tipped with a secreting organ, as in 

 the Sun-dew, or arises from one, as in the Borage 

 Tribe ; and the Ipnphatic, in which there is no secret- 

 ing organ present, beyond the cell or cells of the hair 



