18 DROSERA ROTUNDIFOLIA. (Crap. I. 
CHAPTER II. 
Tur MOVEMENTS OF THE TENTACLES FROM THE CoNnTACT OF SOLID 
Bopies. 
Inflection of the exterior tentacles owing to the glands of the dise being 
excited by repeated touches, or by objects left in contact with them— 
Difference in the action of bodies yielding and not yielding soluble 
nitrogenous matter—Inflection of the exterior tentacles directly caused 
by objects left in contact with their glands—Periods of commencing 
inflection and of subsequent re-expansion—Extreme minuteness of the 
particles causing inflection—Action under water—Inflection of the ex- 
terior tentacles when their glands are excited by repeated touches— 
Falling drops of water do not cause inflection. 
I witt give in this and the following chapters some of the 
many experiments made, which best illustrate the manner 
and rate of movement of the tentacles, when excited in 
various ways. The glands alone in all ordinary cases are 
susceptible to excitement. When excited they do not them- 
selves move or change form, but transmit a motor impulse to 
the bending part of their own and adjoining tentacles, and 
are thus carried towards the centre of the leaf. Strictly 
speaking, the glands ought to be called irritable, as the term 
sensitive generally implies consciousness; but no one 
supposes that the Sensitive-plant is conscious, and, as I have 
found the term convenient, I shall use it without scruple. I 
will commence with the movements of the exterior tentacles, 
when indirectly excited by stimulants applied to the glands 
of the short tentacles on the disc. The exterior tentacles 
may be said in this case to be indirectly excited, because 
their own glands are not directly acted on. ‘The stimulus 
proceeding from the glands of the disc acts on the bending 
part of the exterior tentacles, near their bases, and does not 
(as will hereafter be proved) first travel up the pedicels to 
the glands, to be then reflected back to the bending place. 
Nevertheless, some influence does travel up to the glands, 
causing them to secrete more copiously, and the secretion to 
become acid. This latter fact is, I believe, quite new in the 
physiology of plants; it has indeed only recently been esta- 
blished that in the animal kingdom an influence can be trans- 
