421 



The oils of these Eucalypts usually contain a fairly large amount of cineol, 

 together with pinene, and in the case of many members belonging to these 

 groups, the cineol increases in amount when the oils are stored. By reason of 

 this peculiarity it was thought that the formation of this deposit was connected, 

 in some way, with this increase in cineol, but the evidence available hardly 

 supports that supposition, particularly as the oils of E. goniocalyx, E. punctata, 

 and E. maculosa have not increased their cineol content during twenty years, 

 although the deposit was quite pronounced in all three. It may also be 

 mentioned that the cineol has increased in the oil of E. eugenioides, and one or 

 two others, in which no precipitate has formed. 



Although the deposit is so insoluble in all organic solvents, except 

 chloroform, yet it has been found in solution in the oil itself in two or three 

 instances, and precipitated when these were fractionated. One sample was 

 distilled in Western Australia from a species growing in that State, and 

 forwarded to us by Mr. C. E. Lane Poole ; another sample was from Queensland, 

 and sent to us by the late Mr. P. McMahon. In neither case was botanical 

 material available, so that the species remain undetermined. 



Plate LXXXVIII will serve to show the appearance of the deposit after the 

 precipitation was complete, and the amount so derived from the quantity of oil in 

 the bottle. When originally placed in the show-case the oil was quite clear. 



The following list records the species in the oils of which this deposit has 

 formed. The percentages of cineol in the crude oils, when first distilled, are given, 

 also percentages in some of the same samples about twenty years afterwards ; in 

 both cases the determinations were made by the phosphoric acid method : 



In the diagram illustrating the article dealing with the probable evolution 

 of the Eucalypts, all the above species will be found towards the left, and if a 

 line be drawn from E. maculata to E. tereticornis, and another from E. tereticornis 

 to E. apiculata, not one of the species in the above list will be found to the right 



