150 



HISTORY OF THK VEGETABLE KINGDOM. 



but it appears from the observations of Mr 

 Dryandi, to be the produce of a species of styrax, 

 a tree which grows in Sumatra, and is known 

 as the styrax henzoin. It flows from incisions 

 made in the trunk, and comes into Europe in 

 masses of a light brown colour, variegated with 

 yellow specks. It is brittle, with a vitrious 

 fracture. It is soluble in alcohol; when rubbed 

 it emits a fragrant odour; and when heated the 

 benzoic acid is sublimed in the form of white 

 crystals. It is used in medicine and perfumery. 



Storax. This balsam is obtained from the 

 styrax officinale, a tree which grows in France, 

 Italy, and the islands of the Levant. It is ex- 

 tracted by means of incisions, and concretes into 

 cakes or masses of an irregular form, and a brown 

 or reddish colour. Its taste is spicy, and its 

 smeU fragrant : it is employed in perfumery. 



Styrax. This substance is a semi-fluid juice. 

 The tree from which it flows is cultivated in 

 Arabia; but the true species has not yet been 

 ascertained. It is known to the natives by the 

 name of rosamallos. The balsam procured from 

 it is greenish, its taste aromatic, and its smell 

 pleasant. It is a combination of benzoic acid, 

 and resin, and is used in medicine occasionally. 



Balsam of Tolu. This substance is the pro- 

 duct of a tree of South America, the toluifera 

 balsamum. It flows from incisions made in the 

 bark, and is brought to Europe in small gourd 

 shells. Its colour is brown, and its smell very 

 fragrant. It is employed in medicine, and was 

 at one time thought efficacious in diseases of the 

 lungs. 



Balsam of Peru. This' balsam is obtained 

 from the myroxylor Pcruiferum, a tree which is 

 found in South America. It is extracted by 

 boiling the twigs in water; after evaporation the 

 extract is put into cocoa nut shells, and in this 

 state brought to Europe. It resembles the bal- 

 sam of tolu in its chemical properties, as far as 

 they have befen hitherto examined, and is ap- 

 plied to the same medical purposes; but its con- 

 sistency is less solid, and it is more easily vola- 

 tilized by heat. 



Camphor. This substance was unknown to 

 the Greeks and Romans, but appears to have 

 been first brought into notice by the Arabian 

 physicians. Sotius is the first person who 

 notices it under the name of kamphur. A great 

 variety of plants, especially the labiatce, contain 

 camphor, such as thyme, rosemary, lavender, 

 zedoary, sassafras; but it is chiefly obtained from 

 the laurus camp/iora, a tree which grows in 

 Japan and the islands of the East Indies. In 

 order to obtain it, the root and stem of the 

 plant are cut into small pieces, and put into a 

 large alembic furnished with a head, and con- 

 taining some water. When sufficient heat is 

 applied, the camphor sublimes in the form of 

 small grayish grains, which are afterwards 



worked into larger masses by fi-iction. In this 

 state it is impure, but it is afterwards refined by 

 a second distillation. Camphor, when pure, is 

 a white brittle substance, forming octagonal 

 crystals, or square plates. Its taste is peculiarly 

 hot and acrid, leaving afterwards a sensation of 

 cold; its odour is strong and aromatic. When 

 broken into small fragments and put into water, 

 on the surface of which it swims, a singular 

 phenomenon ensues. The water surrounding 

 the fragments is immediately put into commo- 

 tion, advancing and retiring in little waves, and 

 attacking the fragments with violence. The 

 minuter fragments are driven backwards and 

 forwards upon the surface, as if impelled by 

 contrary winds. If a drop of oil is let fall on 

 the surface of the water, it produces an imme- 

 diate calm. This phenomenon has been attri- 

 buted to electricity. Fourcroy thinks it is 

 merely the effect of the affinities of the camphor, 

 water, and air, entering into combination. 



Camphor is not altered by exposure to the air, 

 but it is so volatile that it evaporates completely, 

 if exposed to it in warm weather. It is insolu- 

 ble in water, to which, however, it communicates 

 its peculiar odour. It is readily soluble in al- 

 cohol; and in the acids its solution in nitric acid 

 forms what is called oil of camphor. It melts 

 at the temperature of 800°, and is so inflamma- 

 ble that it will burn even on the surface of the 

 water. It bums with a bright flame, and leaves 

 no residuum. If formed into a paste with water 

 and alumina, and distilled in a glass retort, the 

 products are volatile oil, camphoric acid, car- 

 bonic acid gas, and carburetted hydrogen gas, 

 with a residuum of charcoal and alumina, in 

 such proportions as to warrant the conclusion 

 that the ultimate ingredients of camphor are 

 carbon and hydrogen. 



Camphor is much employed in medicine. It 

 is regarded as a powerful stimulant and anti- 

 spasmodic. It is particularly offensive to insects, 

 and is frequently used as a preservative in cabi- 

 nets of natural history. 



Caoutchouc. This substance was introduced 

 into Europe about the beginning of last century; 

 and from its being applied to rub out the stains 

 of black-lead pencils, it got the name of India 

 rubber. It is obtained from at least two trees, 

 natives of South America, the jatropa elastica, 

 and hcevea caoutchouc, and from the feus indica, 

 artocarpus integrifolia, and urceola elastica of the 

 East Indies. If an incision is made into the bark 

 of any of these plants, a milky juice exudes, 

 which, when it is exposed to the air, concretes 

 and fomis caoutchouc. As the object of the na- 

 tives in collecting it had been originally to fonn 

 it into vessels for their own use, it is generally 

 made to concrete in the form of bags or bottles. 

 This is done by applying the juice, when fluid, 

 in thin layers, to a mould of dried clay, and then 



