. 
2 DROSERA ROTUNDIFOLIA. [Cuar. I. 
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 
single 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 (Ceenonympha 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 (disculus: 
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 insects, 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 
Mr. Scott shows that gentle irrita- 
tion of the hairs, as well as insects 
placed on the disc of the leaf, cause 
the hairs to bend inwards. Mr. A. 
W. Bennett also gave another inter- 
esting account of the movements of 
the leaves before the British Associa- 
tion for 1873. In this same year Dr. 
Warming published an essay, in which 
he describes the structure of the 
so-called hairs, entitled, “Sur la 
Différence entre les Trichomes,” &c., 
extracted from the proceedings of 
the Soc. d’Hist. Nat. de Copenhague. 
I shall also have occasion hereafter 
to refer to a paper by Mrs. Treat, of 
New Jersey, on some American species 
of Drosera. Dr, Burdon Sanderson 
delivered a lecture on Dionza, before 
the Royal Institution (published in 
‘Nature,’ June 14, 1874), in which a 
short account of my observations on” 
the power of true digestion possessed 
by Drosera and Dionza first appeared. 
Prof. Asa Gray has done good service 
by calling attention to Drosera, and 
to other plants having similar habits, 
in ‘The Nation’ (1874, pp. 261 and 
232), and in other publications. Dr. 
Hooker also, in his important address 
on Carnivorous Plants (Brit. Assoc., 
Belfast, 1874), has given a history of” 
the subject. [A paper on the com- 
parative anatomy of the Droseracex 
was published in 1879 by W. els as. 
a Dissertation at Breslau] 
