2 9 2 
Notes. 
by placing branches in air-tight connexion with a closed vessel of 
water communicating with a mercurial barometer. My experiments 
were made with not very large branches, and were few in number as 
they had to be suddenly brought to a close ; but some of the results 
were sufficiently striking. Thus, with a branch of Cherry-laurel, the 
mercury sank 190 m.m. in four hours; that is, the suction-force of 
the branch was equal to one-fourth of an atmosphere. 
I am now resuming the experiments, substituting a Bourdon’s 1 
vacuum-gauge for the mercurial barometer, and with still more striking 
results. Thus, a vigorous branch of Beech, bearing about 1,100 leaves, 
gave an indicated suction-force of rather over twenty-one inches of 
mercury (about 530 m.m.) within one hour. As I did not succeed in 
obtaining a higher reading, I am inclined to regard this as a measure of 
the suction-force of this branch. The record is briefly as follows : — 
2-40 p.m. indicator of gauge = o inches of mercury 
2*50 „ 
)> 
j) 
= 14 
33 
33 
3 ’°° » 
55 
>> 
00 
M 
II 
33 
33 
3-25 0 
>> 
)) 
= 21 
S3 
33 
3*40 „ 
33 
— - 21 
33 
33 
Some indication of the nature of the relation between the suction- 
force and the leaf-area of a branch is afforded by the remarkable fact 
that the gradual reduction, to the extent of 900, of the number of 
leaves borne by the above-mentioned branch of Beech, produced no 
proportionate — or even perceptible — diminution in the indicated 
suction-force. Full details will appear in a subsequent number of 
the Annals. S. H. VINES. 
THE DIGESTIVE FERMENT OF NEPENTHES.— In view 
of statements which have appeared of late years throwing doubt 
upon the digestive function of the pitchers of Nepenthes , and upon 
the possibility of obtaining from them a peptic enzyme, I have thought 
it worth while to repeat the experiments on the subject which I made 
in the year 1876. I propose to publish a full account of these 
repeated experiments in a future number of this periodical : but 
I think it well to take this early opportunity of stating that, so far as 
the work has been carried at present, the results completely accord 
with those at which I arrived twenty years ago. 
S. H. VINES. 
1 The Bourdon’s gauges used in these experiments were kindly lent to me by 
Messrs. Elliott Bros, of St. Martin’s Lane, London. 
