trine; and I thought you would like to hear of
this. He ends with a delightful sentence. "No science affords more scope
or easier ground for the caviller and controversialist; and these do
good by preventing scholars from giving more force to generalisations
than the master propounding them does, or meant his readers or hearers
to give."

You will blush with pleasure to hear that you are of some use to the
master.

LETTER 666. TO J.D. HOOKER. [February, 1864?]

I shall write again. I write now merely to ask, if you have Naravelia
(666/1. Ranunculaceae.) (the Clematis-like plant told me by Oliver),
to try and propagate me a plant at once. Have you Clematis cirrhosa? It
will amuse me to tell you why Clematis interests me, and why I should
so very much like to have Naravelia. The leaves of Clematis have no
spontaneous movement, nor have the internodes; but when by growth the
peduncles of leaves are brought into contact with any object, they bend
and catch hold. The slightest stimulus suffices, even a bit of cotton
thread a few inches long; but the stimulus must be applied during six
or twelve hours, and when the peduncles once bend, though the touching
object be removed, they never get straight again. Now mark the
difference in another leaf-climber--viz., Tropaeolum: here the young
internodes revolve day and night, and the peduncles of the leaves are
thus brought into contact with an object, and the slightest momentary
touch causes them to bend in any direction and catch the object, but as
the axis revolves they must be often dragged away without catching, and
then the peduncles straighten themselves again, and are again ready to
catch. So that the nervous system of Clematis feels only a prolonged
touch--that of Tropaeolum a momentary touch: the peduncles of the latter
recover their original position, but Clematis, as it comes into contact
by growth with fixed objects, has no occasion to recover its position,
and cannot do so. You did send me Flagellaria, but most unfortunately
young plants do not have tendrils, and I fear my plant will not get them
for another year, and this I much regret, as these leaf-tendrils seem
very curious, and in Gloriosa I could not make out the action, but
I have now a young plant of Gloriosa growing up (as yet with simple
leaves) which I hope to make out. Thank Oliver for decisive answer about
tendrils of vines. It is very strange that tendrils formed of modified
leaves and branches should