8i4 



After these wounds are closed, the influence of the bending is still 

 always noticeable in a production of wood which takes place more vigorously 

 on the under side than on the upper side. The arrangement of the newly 

 formed wood (Fig. 193 h) follows, on the under side, the wavy line caused 

 by the cone of parenchyma wood (/?/'). In contrast to the scantier, simul- 

 taneously produced elements of the upper side of the bent place, the prosen- 

 chyma cells of the under side are at first shorter and arranged bluntly against 

 one another, with broad w^alls. Further, more abundantly divided wood 

 cells and rows of wood parenchyma (hp'), filled with starch, are found on 

 the under side between the thick-walled parenchymatous elements. 



On account of the limited space considerable parts of the tissue have 

 been omitted in the drawing; also part of the normal wood, formed before 

 the bending, as well ias a part of the transitional tissue produced after the 

 formation of the wood parenchyma and equalizing the bending. In Fig. 

 193, fh indicates the spring wood of the current year, g the spiral elements 

 bordering the pith (mk). In Fig. 194, a indicates the pith cells, which have 

 been loosened by the bending; b, those which have remained uninjured and 

 originate from the upper half of the pith body. 



If the bent twig is investigated above and below the bend, it is found 

 that in the present case the influence of the bending extends on an average 

 over 6 to 8 cm. 



The measurements of the branch, chosen for the drawings, are as 

 follows : 



Its thickness amounted to 4.65 mm. beneath the bend, 5.50 mm. at the 

 bend and 5.06 mm. above it. The bark showed toward the tip a considerable 

 increase in thickness. 



The thickness of the wood, before the treatment, amounted to 



-f, , , , , ( upper side 62.0 per cent. "1 



below the bend | ^^-^^^^ ^.^^ ^^^ .< I ^^ ^j^^ ^^,^^^^ cylinder existing 



. I 1 , ( upper side 50.6 " 1 at the time of the measure- 



I under side 35.2 " ( ment, and strengthened by 



Above the bend I ''^Y' '■'I'' ^'^"^ '^ 1 ^"^^^"^"^"^ ^''''''^^'- 



( under side 51.4 J 



The increase in growth from the time of bending up to the time of 



investigation amounted to 



Autumn \\'ood 



Below the bend j "PP^^ ^}f 3i-0 per cent. 

 ( under side 31.9 



At the bend I "Pg^'' ^\'\^ 39-o " 

 ( under side si -8 



Above the bend j "PPer side 28.1 " 

 ( under side 27.2 



Therefore, the increased wood growth is comparatively greater on the 

 upper side of the bend than above and below the bent place in spite of the 

 great tension which may prevail on the convex side within the bend due to 



