128 



conspicuous figure here. The transfusion tracheids can be seen at the lower left and 

 right of the picture with their pitted cells, where also come into vision portions of 

 phloem and xylem of the central axis. The epidermal cells are conspicuous at the 

 top of the picture on the two portions of the convex dorsal surfaces, below which 

 on the extreme right are four hypodermal cells just brought into the picture. 

 In Figure 'j'j is given a longitudinal section through a node showing an oil cell in 

 situ in the concrescence and part of the free portion of the leaf. Figure 78 is a 

 longitudinal section through the junction of two whorls, and showing the position 

 of stomata on the ventral surface of the lower left leaf, where they appear as o\-al 

 bodies, the aperture being indicated by a white line. 



(c) Chemistry of the Leaf Oil. 



Under this species are given results derived from the in\-estigation of a 

 considerable amount of material, gathered in various localities widely apart, and 

 spreading over several years. 



It will be seen that there is a remarkable uniformity in the oil of this 

 species, no matter where the trees are grown, and that in some of its characters 

 it is distinctly different from the oil of any other species of Callitris, excepting 

 that of C. p roping ua of South Australia. 



The comparative constanc}' of the oil from this species cannot now be 

 questioned, and what is true of this species appears also to be true of any other 

 well-defined species of Callitris. 



We have worked somewhat extensively on this species because it is more 

 largely distributed than any other, and is the common tree in the interior of New 

 South Wales. 



The distillations were continued for six hours in nearly all cases, as it was 

 found that a fair quantity of oil came over during the fifth hour. 



The main constituents of the oils of all the samples of C. glauca were the 

 same, and the higher boiling fractions in all cases were highly dextro-rotatory, 

 due to the presence of dextro-rotatory bornyl-acetate and dextro-rotatory borneol. 

 The comparative uniformity of results with the several fractions, obtained with 

 the five samples redistilled, can be seen from the tabulated results (Table II at 

 end of article;. The crude samples of oil were mostly slightly yellowish in tint, 

 and only one or two were reddish in coloin- ; tliis was mostly due to the material 

 being distilled in iron vessels. When cleared by dilute aqueous solution of soda, 

 the oil was almost colourless, being slightly yellowish in tint. AMicn roctiliod by 

 steam, or by direct distillation, it was quite colourless. In both odour and appear- 

 ance the leaf oil of this species of Callitris compares favourably with the better 

 *' Pine-needle oils" of commerce, and the yield is also very good. 



