194 
place along the lines of greatest strain. Thus, when the pressure 
is oblique, the lateral diameter increases much more relatively, 
than the antero-posterior diameter does. 
Hooks attached to fixed support. Hooks attached to fixed support. 
Strain lateral and oblique. Slightly lateral strain. 
attached. — unattached. attached. opposite. unattached. 
S-S A-—P S—S S—S A—P S—S 
a. After 2 weeks. 250 . 360 f180 . 37 70] Fe lstmeasurement. 70 . 112 [ 72. 130] 
eS ee ee 300 . 370 [190 . 365] After 3 weeks. 150 . 287 [105 . 220] 
AG 60 . 100 [ 70 . 105) Hook and support at ty angles. 
ao 3 weeks. 200 . 330 [115 . 245]|g. After 3 weeks. 385 . 590 [150 . 350] 
4 85 . 473 [187 . 395] | A. ( 1st measurement. 120 . 210 [115 . 200] 
Fy ixinceninenient 110 . 250 [105 . 240} After 4 weeks. 345 . 430 [140 . 255] 
After 6 weeks. 620 . 660 [195 . 305] 
The breaking strain for the attached hooks (g) averaged 4 
kilogrammes, for the unattached, 1 kilo; that for the attached 
hooks (e) averaged 8 kilo’s, that for the unattached 2 kilo’s, whilst 
for the parent stem (580 . 520) the longitudinal breaking strain 
was 90 kilo’s. The hook always breaks at the point of attach- 
ment, where it curves around the support, the basal part 
remaining attached to the parent stem. This explains the fact, 
that the greatest relative increase in thickness of the normally 
attached hook, as compared with the unattached one, takes 
place a little way from the base, and extends some distance 
along the first part of the curved portion, at the apex and 
extreme base the difference in thickness between the attached 
and unattached hooks being less marked. 
A hook of Uncaria fixed around an Unearia stem and partly 
clasped by two other hooks (0. 530 and 398 . 480), attained 
after 3 months $20 and 730 in thickness , the opposite hook 
loosely clasping a petiole being 255 ; 410. The larger hook 
supported a strain of 13 kilo’s, and broke with 15 kilo’s. A stem 
of Uncaria, 3 metres long, weighed when fresh, and with the 
branches, leaves and hooks, attached, 1400 grammes. Hence 
the utmost a single adult fifty attached hook can support, 
Ep Slo myles 2.7 ri eeean ae Ma eth ull eapaa eee TSE gee Re A ei peta eect ee emesis oer = Gab la ae ean a 
