OLEOEESIST PRODUCTION. 



15 



the 1917 material was cut it was obvious (fig. 2) that the number of 

 resin passages present by June or July in the 1917 ring was greater 

 than in the 1916 ring ; and at no time in 1917 was the maximum num- 

 ber of resin passages in the 1916 ring as great as the maximum num- 

 ber in the 1917 ring. If, on the other hand, the number of resin 

 passages present in the July, 1916, material cut in 1916 (fig. 1), is 

 compared with the 1917 material cut in 1917, it is apparent that 

 approximately similar numbers of resin passages were present. 





































































































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Apr. MoyJvna July Auq. Sepr, Oct. Ab* Dec. Apr May Juna Ju/y Aug. Japr. Oct Nok Pzc 

 Fig. 3. — Double trees, 1916. 



Number of traeheio's, observed April to 

 December; in 1916, growth ring. ° Sum- 

 ner wood pn sent. 



Number of resin centers per unit area 

 (an arbitrary tangential extent ; diameter 

 af microscopic field by the width of the 

 annual ring observed). Observed April to 

 December', 1916; in 1916, growing ring; in 

 1915, completed ring. 



The conclusion therefore seems justified from this and other data 

 -Hue of the resin passages are shorter than others, and are en- 

 tirely cut away ;is chipping progresses! The microscopic observa- 

 tions indicate thai in the case of the standard tract, the trees, judged 

 by their wood formation in the neighborhood of the faces, a region 

 where the wound response is very pronounced, did not suffer seri- 

 on-lv from the effects of turpentining by this method for ;i two year 

 period. 'I he wood formation was reduced more than in the case of 

 the narrow chipping, as is brought out in the comparisons given in 

 Tables 2 to 4. From Table 2. for instance, it is apparent thai in 



