248 



HARDWICKE'S SCIENCE-GOSSlf. 



seen in commerce. The raw material is mixed with 

 lime, and again sublimed into glass vessels of a 

 special shape, which are ultimately broken away, 

 leaving the camphor in the form of concavo-convex 

 cakes from two to three inches thick, with a hole in 

 the middle ; when it is solid, colourless, and trans- 

 lucent, with a penetrating aromatic odour, and a 

 bitter pungent taste, with a crystalline consistency. 

 Its specific gravity is less than that of water, conse- 

 quently it floats on water, and evaporates, undergoing 

 a curious rotary movement while doing so ; but little 

 soluble in water, freely so in alcohol and ether, 

 also in volatile and fixed oils : At ordinary tempera- 

 tures it slowly evaporates' and crystallises on vessels 



hysteria, and in nervous and typhoid fever. If taken 

 in small quantities in solution, it is said to strengthen 

 the teeth. It is employed in domestic economy as a 

 protective agent against the attacks of insects, and 

 for a similar purpose by natural history collectors. 

 It is frequently used as a preventive against infec- 

 tious diseases, although its power in that direction is 

 not great. 



Borneo or Sumatra Camphor. — This is another 

 variety of camphor produced by Dryobalanops aro- 

 matica, Gaert., belonging to the distinct family Dipte- 

 rocarpccc, and which was for a long time erroneously 

 supposed to be the tree which produced the kind 



Fig. 167. — Cinnammmitn Ccunphora, Nees et Eb. 



in which it is contained, as in glass jars for instance. 

 It melts at a temperature of 28S , and boils at 400 , 

 is very inflammatory, burning with a blue flame. 



The uses of camphor are very numerous, and its 

 actions are equally various. When taken internally 

 its action is chiefly upon the nervous system, in 

 moderate doses producing exhilaration, quietude and 

 placidity of feeling, allaying irritation. In large 

 doses the circulation, especially in some persons, 

 such as those suffering from heart affections, may be 

 effected in a similar way, passing off afterwards 

 through the skin and bronchial membranes, but not 

 by the urine. In excessive doses it is narcotic and 

 poisonous. It is chiefly employed in medicinal 

 practice as an anodyne in nervous affections and 



met with in European commerce. This tree also 

 yields the oil of camphor, or liquid camphor, as it is 

 frequently called, wbich is obtained by incision from 

 the younger trees, a practice which eventually destroys 

 the trees. It "has, however, the same properties as 

 the solid camphor, and would have ultimately de- 

 veloped into that substance if the trees had been left 

 unmolested. The solid camphor of this tree is found 

 in the cracks of the bark in large blocks, varying 

 according to the age of the tree ; and to obtain it the 

 trees are cut down, split into blocks, and the 

 camphor extracted. In the Museum No. I, in the 

 Royal Gardens, Kew, the crystallised camphor is 

 shown in siht upon the wood, so there is a great 

 difference between the development of camphor in the 



