OLEOEESIN PRODUCTION. 



23 



Production of resmiferous tissue. — Many more resin passages than 

 are normally present were formed in the wood which developed after 

 wounding. (Figs. 5 and 6.) 



In both the 1916 and 1917 rings the greatest number of resin 

 passages per unit area was present in the specimens from the narrow- 

 chipped trees, although the average number present in the 1915 

 ring, when the timber had not been turpentined, chanced to be smaller 

 (Table 4) than in the case of either the standard or the double 

 specimens. In 1916 the earliest formation of resin passages was 

 also found in the narrow-tract specimens. 













































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A for Apr Mov JunaJo/v Auq. Sep/: Ocr. A/or. Mar/lpr. May June. July Aaa. Sapr. Oct Nov. 



Fig. 0. — Narrow trees, 1917. 



Number of tracheitis, Observed March to 

 November; In 1017, growth ring. "Sum- 

 mer wood present. 



Number of resin centers per unit area 

 (an arbitrary tangential extent ; diameter 

 of microscopic field by the width of the 

 :i nnuM 1 ring observed). Observed March I" 

 November, 1017; in 1915, 1916, and 1917, 



growth rings. , 19ir> ; , 191G ; , 



1917. 



At the level of the 1917 chipping, fewer resin passages per unit 

 ;m<-:i v- <■!•!• pre.-ent. in Hie 1916 rings than at the lower levels, judging 

 the latter from the Spe'cfmiens studied during their development in 

 the l!»l<; growing season. This was also true in the oilier two 

 methods practiced. Sonic, but noi all, of the resin passages iixlueed 

 hv #OUnding were therefore apparently relatively short and appear 



to have 1 been cul away as chipping progressed up the tree. 

 The rargesl resin passages found in the narrow material collected 



in \U\7 were pre-ent in the |!)|(i ring, whieh was prndmed during 



the lir.-.t year of turpentining. The year 1916 was found, further- 



