278 GLANDULAR HAIRS: [Cuar. XV, 
intersecting spiral lines. Whether these lines are the result 
of contraction from the drying of the walls, I do not know, 
but the whole pedicel was often spirally rolled up. These 
glandular hairs are far more simple in structure than the so- 
called tentacles of the preceding genera, and they do not 
differ essentially from those borne by innumerable other 
plants. The flower-peduncles bear similar glands. The 
most singular character about the leaves is that the apex is 
enlarged into a little knob, covered with glands, and about 
a third broader than the adjoining part of the attenuated 
leaf. In two places dead flies adhered to the glands. As 
no instance is known of unicellular structures having any 
power of movement,* Byblis, no doubt, catches insects solely 
by the aid of its viscid secretion. These probably sink down 
besmeared with the secretion and rest on the small sessile 
glands, which, if we may judge by the analogy of Droso- 
phyllum, then pour forth their secretion and afterwards 
absorb the digested matter. 
Supplementary Observations on the Power of Absorption by the 
Glandular Hairs of other Plants—A few observations on this 
subject may be here conveniently introduced. As the glands 
of many, probably of all, the species of Droseracez absorb 
various fluids or at least allow them readily to enter,f it 
seemed desirable to ascertain how far the glands of other 
plants which are not specially adapted for capturing insects, 
had the same power. Plants were chosen for trial at hazard, 
with the exception of two species of saxifrage, which were 
selected from belonging to a family allied to the Droseracee. 
Most of the experiments were made by immersing the glands 
either in an infusion of raw meat or more commonly in a 
solution of carbonate of ammonia, as this latter substance 
acts so powerfully and rapidly on protoplasm. It seemed 
also particularly desirable to ascertain whether ammonia 
was absorbed, as a small amount is contained in rain-water. 
With the Droseracese the secretion of a viscid fluid by the 
glands does not prevent their absorbing; so that the glands 
of other plants might excrete superfluous matter, or secrete 
an odoriferous fluid as a protection against the attacks of 
* Sachs, ‘Traité de Bot.’ 3rd edit. imbibition, is by no means clearly 
1874, p. 1026. understood: see Miiller’s ‘Physio- 
+ The distinction between true logy,’ Eng. translat. 1838, vol. i. p. 
absorption and mere permeation, or 280, 
