26 HENRY G. SMITH. 



practically no difference could be determined between the 

 oils of these two species, as they both consisted largely of 

 eucalyptol and pinene, with an entire absence of phellan- 

 drene. The aldehyde aromadendral was present in both 

 oils. The barks of the two species, however, differed con- 

 siderably in thickness, but as will be shown later not in 

 chemical constituents, 1 both were identical in this respect 

 and the tannins were alike in both barks. But even with 

 this close botanical similarity and chemical agreement 

 between the constituents of the oils and the barks, it was 

 difficult to understand why a forest tree like that of E. 

 salmonophloia should degenerate into the stunted Mallee 

 growth of E. oleosa. From the results now obtained it 

 may be possible, perhaps, to offer a feasible suggestion as 

 to the origin of this peculiarity, and there seems no reason 

 to suppose that this alteration into the Mallee form is an 

 isolated case. E. salmonophloia and E. oleosa being 

 apparently the same tree in different forms of growth, it is 

 probable that the latter is a stage in the slow and per- 

 manent degeneration of the larger tree. Although E. oleosa 

 is generally seen as a stunted shrub, yet, it often occurs 

 as a persistent tree, and even in New South Wales it is 

 often found having a height of 40 to 50 feet, with a corres- 

 ponding size of trunk. Mr. R. H. Oambage informs me 

 that in his experience, E. oleosa is found in tree form 

 more often than any other species of Mallee. In both E. 

 viridls and in E. Morrisi trees are often found which 

 have reached to a fair size, but the tendency to early decay 

 appears to be marked in Eucalyptus species which most 

 often take the Mallee form of growth. 



It is generally accepted by physiologists that oxalic acid 

 is poisonous to plants as well as to animals, and in Sachs' 



1 This was also the case with the thin and the thick barks of the 

 " Mallet " of West Australia, E. oecidentalis. 



