2 DROSBRA ROTUNDIPOLIA. [Chap. I. 



a dozen plants, bearing fifty-six fully expanded leaves, and 

 on thirty-one of these dead insects or remnants of them 

 adhered; and, no doubt, many more would have been caught 

 afterwards by these same leaves, and still more by those as 

 yet not expanded. On one plant all six leaves had caught 

 their prey; and on several plants very many leaves had 

 caught more than a gingle insect. On one large leaf I found 

 the remains of thirteen distinct insects. Flies (Diptera) are 

 captured much oftener than other insects. The largest kind 

 which I have seen caught was a small butterfly (CcBnonympha 

 pamphilus) ; but the Rev. H. M. Wilkinson informs me that 

 he found a large living dragon-fly with its body firmly held 

 by two leaves. As this plant is extremely common in some 

 districts, the number of insects thus annually slaughtered 

 must be prodigious. Many plants cause the death of insects, 

 for instance the sticky buds of the horse-chestnut (^sculus 

 hippocastanum), without thereby receiving, as far as we can 

 perceive, any advantage ; but it was soon evident that Drosera 

 was excellently adapted for the special purpose of catching in- 

 sects, so that the subject seemed well worthy of investigation. 



The results have proved highly remarkable; the more 

 important ones being firstly, the extraordinary sensitiveness 

 of the glands to slight pressure and to minute doses of certain 

 nitrogenous fluids, as shown by the movements of the so- 

 called hairs or tentacles; secondly, the power possessed by 

 the leaves of rendering soluble or digesting nitrogenous sub- 

 stances, and of afterwards absorbing them; thirdly, the 

 changes which take place within the cells of the tentacles, 

 when the glands are excited in various ways. 



It is necessary, in the first place, to describe briefly the 

 plant. It bears from two or three to five or six leaves, gfener- 

 ally extended more or less horizontally, but sometimes stand- 



oocaKlon heronfter to refer to a onlllnR attention to Drosera, and 



Saper by MrH. Trent, of New to other plantH having similar 



eney, on Home American Ki>e- hnliltH, In The Nation ' (1S74, 



cles of Drosera. Dr. Itiinlnn pp. 2itl nnd 2.TJ), and In other 



Bandpraon delivered a lecture on puhllcatlonH. Dr. Hooker also, 



DIooaea. before the Royal lUHtItu- In his Important address on Car- 



tion (publlHhe<l In ' Nature,' June nivorous rinuts (Itrlt. Assoc., 



14, 174), In which a short nc- Helfnst, 1874). has KlVen a hls- 



count of my observntlons on the tory of the 8nbje<"t. [A paper on 



power of true digestion pos- the comparative anatomy of the 



eased by Drosera and Dlona?a Droseracejp was published In 

 nmt app(>ared. Professor Asa 1870 br W. Oels "" 



Gray has done good service by tlon at Brealau.] 



