90 
Journal of the Mitchell Society [November 
These results show a wide variation in the optical rotation of 
the volatile oils from the individual trees, even among trees of the 
same species. In a general way the figures give support to Long’s 
view, namely that the volatile oils from Pinus palustris are 
dextro-rotatory and those from Pinus heterophylla levo-rotatory. 
That this is not strictly true, however, is evidenced by the dextro- 
rotation of A, (P. heterophylla ) and more especially by the levo- 
rotation of C 3 (P. palustris). 
With these variations in the first collection from the several 
trees, the question naturally arose, would the variations change as 
the season advanced or would the figures prove constant for the 
individual trees? The rotations for the successive collections fol- 
low in Table II : 
Table II. — Optical Rotation in 100 mm. Tube, 20° C. 
Collection A1 
A2 
A3 
A4 
A5 
A6 
Cl 
1.. 
— 20°5 O' 
-f-0°15' 
—15 
O Q, 
-fl5°40' 
-4-8° 9 1 
+18°18' 
— 27°11/ 
2.. 
—22° 5' 
— 0°30' 
—14 
° 26 ' 
-hl5°22' 
+8°50' 
-f-17°43 / 
— 26°48' 
3.. 
— 21°45 / 
+0°15 / 
—15 
°55 / 
-fl4°15 / 
+8°27 / 
+19°30 / 
— 26°25 / 
4.. 
—21° V 
— l 0 ^ 
—15 
°50' 
-fl4°20 / 
-f-8°34 / 
+18°46 / 
— 23°32 / 
5.. 
— 20°30 / 
U"> 
0 
CS 
1 
—15 
°15 / 
+14°21' 
+8°32 / 
+19°24 / 
— 21°12 / 
6.. 
— 20°15' 
— 3°3 O' 
—15 
°27*' 
+14°35 / 
+8° V 
+ 18 ° 1 & 
— 21°46' 
7.. 
— 22°15' 
— 5°45' 
—17 
°52^ 
+12°49' 
+7° & 
+14°47' 
— 21°35' 
Collection C2 
C3 
C4 
Dl 
D2 
D3 
D4 
1.. 
— 26°28' 
— 7°26 / 
+ 7 
°31' 
+10°50' 
+1°23' 
— 18°35 / 
— 29°26' 
2.. 
— 25°37 / 
— 6°42 / 
+ V 
3 20' 
+U°23f 
+2 °40' 
—17° 0, 
— 27°45' 
3.. 
— 26°2 O' 
— 4°45' 
+13° 7/ 
-f-2°25 / 
— 15°2 O' 
— 28°19' 
4.. 
— 26°30 / 
— 4°29' 
-f 12°46 / 
+2°25' 
—15° O' 
— 27 ° 38 ' 
5.. 
—26° 7/ 
— 3°55' 
+13° 0' 
+i°iy 
— 14°38' 
— 27°4 8' 
6.. 
—26° O' 
—4° 5' 
+13° 0/ 
+1°15' 
—14° 7 < 
— 26°11' 
7.. 
— 26°28' 
—6° 6/ 
+10°48' 
— 0°55 / 
— 14°19' 
— 26°12' 
Note. — T he yield of oleoresin from C4 was so small, after the first and second col- 
lections, that not enough volatile oil could be obtained on distillation to fill the 100 mm 
tube. 
From this table it is seen that the rotation in most cases is quite 
constant throughout the year. The most marked exception is A, 
(P. heterophylla) . It is evident that some distinct change in the 
biological activity of this tree has taken place, for while the rota- 
tion is reasonably constant during the first half of the year, a 
steady increase in the levo-character of the oil is apparent during 
the last half. In the case of C, (likewise P. heterophylla) some- 
