130 
Numerous enquiries on the subject began to reach Kew and 
investigations were immediately instituted. Requests were sent 
out to the various Colonies where aberrant trees grew, asking 
that experiments might be made and that botanical specimens 
and full notes on their plantations might be sent to the Royal 
Botanic Gardens. 
From these notes and from the recorded experiences of former 
practical exploiters as to the variations in the yield of camphor 
trees, the following notes have been drawn up as to the best 
way of establishing paying plantations. 
The all-important matter to the camphor exploiter is the 
proportion of Camphor that a tree yields. The actual per- 
centage of solid camphor obtainable and to a less extent the 
percentage of the various constituents of the oil—safrol, cineol, 
eugenol, etc.—determine the value of the tree. Oils are always 
among the by-products of camphor production, for the solid 
substance obtained from the distillation of the wood or leaves 
is invariably mixed with light and heavy essential oils. An 
‘oil tree” is not therefore necessarily one that produces only 
oil, but one that yields a large proportion of oil, and that does 
not yield solid camphor in paying quantities. 
Before suggesting means of producing plantations of camphor- 
bearing trees it will be necessary to enquire first into the cause 
of variation of yield and although the endeavour is now to 
obtain camphor by the distillation of the leaves, advantage may 
be taken of the experience of the camphor-wood distillers to 
throw some light on the cause of variation. 
Causes of Variation. 
The direct cause of the presence in the camphor tree of 
essential oils of varying constitution and quantity is to be found 
probably in the formation within the plant of Terpentinol 
(Cro H,,), which is gradually changed by the activity of the 
ving cells into camphor (C,) H,,0O). As this oxidization pro- 
pissed different compounds appear and it is by their 
admixture in the products of the distillation that all the 
different oils and finally camphor itself are formed. (Grasmann 
in Mitt. Deutch. Gesellsch. vi. 303 (1895) and Dubard in Bull. 
Econ. Indo-Chine, 1909, 148). 
If this theory is accepted, it is not surprising to find that the 
yield of camphor varies from month to month. Mr. Oishi 
writing in the Chemical News as early as 1884 (1. 74) enumerates 
a series of measurements to prove that much more camphor is 
obtained in Japan from camphor wood cut in the cool season 
than from that cut in the summer. The same observation was 
made by Mr. W. R. Price, writing from Formosa in 1912, as 
tending to account for the presence of so-called “ oil trees ”’ in 
that country. The cause of variation in the recorded yield of a 
tree in the Government plantation at Curepipe in Mauritius is 
