. 
234 General Notes. [ April, 
hered for four feet and then swung away for two feet, reattaching above, 
had the pith decidedly more central at the detached part than at points 
either above or below. The extreme case to which I referred, where the 
pith actually ran through a tube slightly raised above the outer surface, 
showed a transition from this state of extreme eccentricity to one of 
centrality in the space of one foot where the vine suddenly abandoned 
its support. 
The function assigned to the rootlets by the hypothesis is one of para- d 
sitism. They are assumed to penetrate the bark as far as the cambium l 
layer, and remove the sap of the tree, appropriating it directly to the i 
ine. This nutrition, being ready-made, would naturally be deposited at 
the nearest point of contact, and thus account for the great preponder- 
ance of woody tissue found on the side next the tree. It would there- : 
fore follow that this eccentricity of pith should not exist where the sup- 
port is not a living tree. To test this question, I sought out a small 
vine of the same species which climbed and closely adhered with a prom 
fusion of rootlets to a perfectly dry stone wall ten feet in height. This 
I examined most carefully, and accurately measured at various points, 
finding the position of the pith uniform at all distances from the ground. 
The following measurement will therefore answer for all: ‘Three feet 
from the base, where the diameter was 43", the pith was 23” from the 
inner and 2" from the outer edge, or within three fourths of a line of 
the centre. 
One other class of instances seemed to bear directly on this point, and 
to these I gave special attention. I refer to vines found climbing fences 
and posts under varying circumstances. The results obtained from these . 
were perhaps the most surprising of all. One 51 in diameter tightly 
hugged a decayed fence post, insinuating its rootlets deeply into the soft 
surface. Of this the pith was 4" from the inner and 14” from the outer 
margin, giving the astonishingly large ratio of 3}. A section of a larger 
stem (11”) similarly situated, and whose rootlets tore away considerable 
of the decayed wood in detaching it, showed the centre of the pith to be 
7"! from the inner and 4! from the outer margin. Considering the size 
of this vine the eccentricity was large. 
Where the wood to which the vines adhered was not decayed or soft, 
a marked diminution in the eccentricity was perceptible. In one m- 
stance where the rootlets clung very tightly to a dry surface, which had 
moreover been charred and where penetration was impossible, the meme 
urements were respectively 34” and 24, or an eccentricity of half a line 
in a diameter of half an inch. 
So far as my observations, which were numerous, extended, it seemed 
to be the law that, ceter’s paribus, the softer the wood to which the 
rootlets adhered, the greater the eccentricity of the pith. 
Without going further into details, therefore, the whole subject may 
be thus briefly summed up :— 
Sag asset a X 
A a 
