ON GUTTA PERCH A, &C. 461 
chloroform. The solution is very thick and like a syrup, but 
can be filtered, if sufficiently diluted. From the filtered liquid 
the pure gutta percha is precipitated by alcohol, then washed 
with alcohol, and dried at 70° to 80°. The crude substance 
must, however, before being dissolved in chloroform, be treated 
with water, alcohol, and ether. Sulphuret of carbon also dis- 
solves gutta percha, which remains behind unaltered, when the 
solution is evaporated. At 70° to 80° it can be moulded with 
facility; at 110° it has the consistency of treacle; at 130° it 
forms an oily liquid, which congeals again when cold, and 
begins to be decomposed. The Getah Malabeoya is also 
dissolved by chloroform. 
By the same treatment with chloroform, caoutchouc can also 
be easily obtained in a pure state, and it then resembles, exter- 
nally, very much Arabic gum. The author tried to reduce the 
gutta percha and caoutchouc by ammonia into an emulsion 
similar to the natural milky juice, but succeeded neither by the 
method of Summers nor by any other method. The ammonia, 
as well as other alkalies, had no other effect upon the gutta, 
except that of extracting from it colouring matter. Neither the 
purified gutta nor the caoutchouc contain nitrogen. In the 
crude gutta traces of it are found, and these are, very likely, 
contained in the extractive-like impurities. Neither could the 
author discover any so-called protein combination, as casein 
(mentioned by Guibourt as a constituent of the crude gutta 
percha). Vulcanized caoutchouc becomes brittle through the 
influence of the air, heat, and moisture ; and Burke has, there- 
fore, recommended sulphuret of antimony to be employed in- 
stead of sulphur for vulcanizing. Gutta percha vulcanized 
with sulphur likewise loses its efficacy in the course of time. 
Vulcanized gutta percha contains 8.35 per cent, of sulphur, 
and caoutchouc 11.3 per cent, of this substance. It is remark- 
able that caoutchouc thus prepared is no longer soluble in 
chloroform. 
By dry distillation, gutta percha yields, at 100°, a yellow oil 
of a penetrating but not disagreeable smell. Between 120° and 
200°, yellow, offensively smelling, oily substances are going off, 
which become darker in the air : at a still higher temperature 
the colour of the very thin distilled product is more red or 
reddish-brown. Fifty grammes of gutta percha, distilled in the 
sand-bath until nothing more passed over, yielded 28.83 
grammes volatile oil of 0.909 sp. grav. ; fifty grammes of 
caoutchouc, however, distilled in the same way, yielded 42.884 
grammes, which contained a considerable proportion of water, 
in consequence of an air-dry substance having been employed, 
and the caoutchouc being able to retain more water than the 
VOL. XXIV. 3 R 
