35% “The Rev. Mr. Keith on the [ApRif,. 
turn upwards ; and that when a pendant stem becomes elevated, 
the elevation does not commence at the point. In support of 
this assertion, I will adduce the faet of the spiral growth of the 
- téndril of the vine. If it followed the rule of elongation implied 
in Mr. Knight’s hypothesis, it could not complete so much as @ 
singlé circumvolution round its supporter (especially if its posi- 
tidn should be horizontal), and yet it completes several circum- 
volutions before it is satisfied with its hold. Further, if plants 
followed thé rule implied in the hypothesis, how should the 
plimelet of the onién ascend in the shape of a loop, or whip and: 
te lash ; or how should beans planted at the depth of a 
foot send up a perpendicular stem with the summits bent 
down in the shape of hooks till they reach the surface ; or how 
Should the frond of Pteris aquiléna come up and continue so long 
circmal; or how should the poppy or crown iniperial be at all 
able to rear their nodding heads? But if we allow the alleged 
elongation to. take place, will it give verticality to the plant? 
{ think it will not. ‘For as the operating cause is capable of 
turnine up the point only, the bend will remain as before ; and 
When a new bend takes place, whether on the same side or on 
the side opposite, it will be the point only that will again ascend ;. 
$0 that the stem will exhibit throughout its whole ‘extent only a 
succession of bends and turn-ups. 
The fact, however, is, that when the pendant stem is elevated, 
the elevation does not commence at the summit, but at the 
lower part of the bend; so ‘that this is a case for which Mr.. 
Knight’s hypothesis furnishes no ‘provision. 
On Sept. 1, 1816, at eight o’clock, a.m. the shoot of a pltim- 
trée was much bent down; the origin of the bend being at. 
least six inches from the summit. At six o’clock, p.m. it had 
beoun to resume ah éréct position by the lower half, though ina 
sort of zigzag, or rather waving line. 
On the 2d, at 11 o’clock, a.m. ‘the process of erection was. 
Still -going on in the saiiie waving line, and the summit slightly 
bent by about two inches. 
‘On ‘the 4th, the waving line was a little higher, and the 
summit bent only by an inch. 
On the 6th, the waving line was quite obliterated, and the. 
shoot ‘vertical; but the summit was the last part ‘that was 
turned up.* 
Also, on April 18, 1818, at six o’clock in the morning, the 
scapes of a batch of daffodils in front of my study were bent 
down to the earth, by means of a sharp frost, so that the 
blossoms Were recumbent upon the grass. At nine o’clock they 
were all erect; but the blossoms were all nodding as before. 
Consequently they were not elevated by any recurvature at the 
summit, nor by any elongation of the fibres of the under side, as. 
* Annals of Philosophy, No. xlvii. 
