EUCALYPTUS GLOBULUS. 63 



Some of the large oil glands so numerous in the leaf, are seen 

 at D containing yet a drop of oil, E. The whole leaf is load- 

 ed with the most beautiful crystals ; see F. Some of these 

 crystals separated from the leaf and greatly magnified are seen 

 in figure 3. The prismatic crystals are calcium oxalates. The 



/'V,V. J. Crystals from the Leaf of Eucalyptus. x?5O diameters. 



botanical name for the rosettes of pointed crystals is raphides 

 and their composition according to Dr. Lionel Beale is most 

 various : 



1. A little organic matter. 



2. Sulphate of lime. 



3. A little carbonate of lime. 



4. Traces of chloride of sodium. 



5. A vegetable salt of lime containing a considerable por- 

 tion, or else consisting entirely of oxalate of lime. 



The virtue of eucalyptus depends upon a volatile oil ; of 

 this oil the fresh leaves yield 2.75 per cent., and the recently 

 dried leaves yield 6 per cent. This oil is composed of two 

 camphors, the larger proportion of which is known as eucalyptol. 



The leaf is supplied with quite large stomates or breath- 

 ing spores or mouths; see figure 4. These stomates connect 

 directly or by means of little openings between some of the 

 palisade cells with the center of the leaf, so that air and 

 moisture are carried all through the leaf between the loosely 

 packed structure, until it reaches the end of a spiral vessel. 



