Balata and the Balata Industry. 177 
Secretary of State, from Sir JOSEPH HOOKER, in 
response to an application which I made to the latter 
gentleman, as Director of the Kew Establishment, on my 
return from the Canje for information on the subject : — 
Dr. Muller says : — " Although my own opinion about Balata, derived 
from personal experience of its practical application in a few instances 
was entirely favourable, I thought it desirable to avail myself of an 
opportunity of obtaining a further opinion, dire6t from an india-rubber 
manufacturer, considering that this would be much more to your pur- 
pose than anything I could say on my own account. Hence the delay 
in my answering your letter. 
" It seems, then, that Balata is by no means neglected, and in fact it 
would find ready purchasers if more of it came to the market. As it is, 
the supply is very limited and generally it comes only once a year. It 
commands a higher price than gutta-percha and this in itself is a proof 
of its usefulness. It is used almost in all cases in which gutta-percha is 
used, but on account of its higher price only for superior purposes." 
" It seems that Balata is treated by the manufacturers simply as a 
superior kind of gutta-percha and therefore its name disappears when 
manufactured." 
" Nevertheless, Balata is distinctly different from gutta-percha, and 
this is especially manifested in some of its physical characters ; for 
instance, it is somewhat softer at ordinary temperature and not so rigid 
in the cold." 
" The chemical composition, however, is probably quite identical with 
that of gutta-percha and of caoutchouc." 
" In one respect, Balata shows a very marked and important differ- 
ence from gutta-percha, and that is in its behaviour under the influence 
of the atmosphere, whilst gutta-percha when exposed to light and air 
soon becomes altered on the surface and changed into a brittle resinous 
substance, into which the whole of the mass is gradually converted, in 
the course of time. Balata on the other hand is but slowly acted upon 
under these circumstances." 
" I enclose a piece of Balata tissue which has now been in my pos- 
session quite six years, and although it shows a peculiar mealy efflor- 
escence, due to chemical change, it is still supple and coherent. A 
similar tissue of gutta-percha would have long before now become 
entirely converted into a brittle resin." 
Y 
