734 Wisconsin Academy of Sciences, Arts, and Letters. 
Recently the composition of certain oils has been applied to 
determining species. 1 On the Pacific coast there occur two spe¬ 
cies of pines, P. ponderosa and P. Jeffreyi, that appear to grad¬ 
ually merge into each other, the intermediate forms being known 
as ‘‘cross variety’’ or “bastard” pine. Identification in the 
field and in the laboratory even by the trained botanist was very 
uncertain. Analyses of the oleoresins from five typical trees of 
each type showed clearly that there was no intergradation be¬ 
tween P. ponderosa and P. J effreyi and that the “cross variety” 
pines should be referred to P. ponderosa. Heptane was found 
only in typical P. J effreyi. 
The eastern form of P. ponderosa occurring in the Rocky 
Mountain region is known as P. ponderosa scopulorum. Some 
botanists maintain a distinction between the two while others 
class them under a single species. It was found, however, that 
the turpentine oils were distinctly different. The oils from the 
P. ponderosa were laevo-rotatory and consisted very largely of 
/?-pinene, while those from P. ponderosa scopulorum were d-ro- 
tatory and contained about 65 per cent a-pinene. The well- 
defined differences between the volatile oils shows that a dis¬ 
tinction between the species and its variety should be main¬ 
tained. 
The cellulose content of the woods was found to be nearly con¬ 
stant both for the conifers and hardwoods especially if the per¬ 
centage content is based on the wood free from water soluble 
and ether soluble constituents. The quantity of pentosans pres¬ 
ent in the hardwoods is considerably greater than in the coni¬ 
fers. This distinction is also maintained in the celluloses. It 
is a striking fact that the pentosan content of the isolated cellu¬ 
loses is practically the same as that of the original wood, point¬ 
ing to distinctly different kinds of cellulose. The quantities of 
methoxy groups and hydrolytic acid obtained from the conifers 
are also smaller than from the hardwoods. 
The wood of the western larch ( Larix occidentalis ) was found 
to contain, about 10 per cent of a galaetan 2 that had not been 
previously described in the literature. This galaetan yielded 
only galactose on hydrolysis. Further investigation showed that 
1 Schorger—“Chemistry as an Aid in the Identification of Species”, Proc. 
Soc. Am. Foresters, 11 (1916) 33-39. 
2 Schorger and Smith, “The Galacton of Larix Occidentalis”, Jour. Ind. 
Eng. Chem. 8 (1916). 
