34 
Journal of the Mitchell Society. [ May 
oleo-resin secreted in the Longleaf pine. Tschirch and Ko- 
ritzschoner have shown that this oleo-resin consists of 
Palabienic Acid — C I3 H 20 0 2 5 per cent. 
7 Palabietic Acid — C JH 30 0 2 — 6 “ “ 
a and/? — Palabietiolic Acid — 0 i6 H 24 O 2 — 56 “ “ 
Spirits of Turpentine 20 “ “ 
Paloresene 10 “ “ 
Impurities, Bitter Principle and Water 3 “ “ 
No study has been published of the oleo-resin from Pinus 
Heterophylla, or Cuban pine, which occurs so frequently in 
the Florida forests and from which therefore so large a pro- 
portion of the present supply of spirits of turpentine and 
rosin is prepared. Such an investigation has been begun in 
the laboratory of the University of North Carolina. 
Many interesting new lines of investigation in this field 
suggest themselves if the chemist instead of waiting for 
specimens to reach the laboratory will study and note the 
changes at the tree. When the oleo-resin first appears it is 
a perfectly clear liquid. In the case of some pines it remains 
thus for weeks and then slow crystallization of the dissolved 
acids begins, with others the crystallization begins within a 
minute after the drop appears. Evidence already in hand points 
to the probability that the clear liquid issuing from the 
resin ducts is a supersaturated solution. To what is this 
condition of supersaturation to be ascribed ? Again, the flow 
of resin is relatively rapid during the first forty-eight hours 
after wounding, then quickly diminishes and practically 
ceases after seven days. Is this cessation to be explained by 
the plant physiologist or by the chemist ? Has the inner lin- 
ing of the resin duct lost its power of production, or has the 
duct been closed by oxidation, or crystallization of the oleo- 
resin which it exudes ? If chemical, can it be prevented by 
some simple means ? A practical solution of this problem 
would be a great blessing to the turpentine operator in these 
days of scarcity of labor and would do more than anything 
