BIR 



BIR 



first examined by Vauquelin, who found 

 it possessed of properties different from 

 every other. It was found collected on 

 the epidermis of a plant brought to Eu- 

 rope by Michuud, and called roblnia vis- 

 cosa, constituting a viscid substance, 

 which made the fingers adhere to the 

 young- twigs. From the late analysis of 

 bird-lime by Bouillon la Grange, it is ob- 

 vious that it owes its peculiar properties 

 to the presence of an analogous substance; 

 which indeed constitutes the essential 

 part of that composition. Hence the rea- 

 son of the name of bird-lime to the prin- 

 ciple itself. 1. Natural bird-lime (or that 

 which exudes spontaneously from plants) 

 possesses the following properties : its co- 

 lour is green ; it has no sensible taste or 

 smell ; is extremely adhesive ; softens by 

 the heat of the fingers, and sticks to them 

 with great obstinacy. When heated, it 

 melts, swells up, and burns with a consi- 

 derable flame, leaving a bulky charcoal 

 behind it. It does not dissolve in water; 

 alcohol has but little action on it, especi- 

 ally when cold. By the assistance of 

 heat it dissolves a portion of it ; but in 

 cooling, allows the greatest part to preci- 

 pitate again. When exposed to the air, 

 it continues glutinous, never becoming 

 hard and brittle, like the resins. It com- 

 bines readily with oils. Ether is its true 

 solvent, dissolving it readily without the 

 assistance of heat. The solution is of a 

 deep green colour. The alkalies do not 

 combine with it ; the effect of the acids 

 was not tried. These properties are suf- 

 ficient to distinguish bird-lime from every 

 other vegetable principle. 2. Artificial 

 bird-lime is prepared from different sub- 

 stances in different countries. The ber- 

 ries of the misletoe are said to have been 

 formerly employed. They were pound- 

 ed, boiled in water, and the hot water 

 poured off. At present bird-lime is usu- 

 ally prepared from the middle bark of the 

 holly. The process followed in England 

 is as follows : the bark is boiled in water 

 seven or eight hours, till it becomes soft. 

 It is then laid in quantities in the earth, 

 covered with stones, and left to ferment, 

 or rot, for a fortnight or three weeks. 

 By this fermentation, it changes to a mu- 

 cilaginous consistency. It is then taken 

 from the pits, pounded in mortars to a 

 paste, and well washed with river water. 

 Its colour is greenish, its flavour sour, 

 and its consistence gluey, stringy, and te- 

 nacious. Its smell is similar to that of 

 linseed oil. When spread on a glass plate, 

 and exposed to the air and light, it dries, 

 becomes brown, loses its viscidity, and 



may be reduced to a powder ; but when 

 water is added to it, the glutinous pro- 

 perty returns. It reddens vegetable blues. 

 When gently heated, it melts and swells, 

 and emits an odour like that of animal 

 oils. When heated on red hot coals, it 

 burns with a lively flame, and gives out a 

 great deal of smoke, leaving a white ash, 

 composed of carbonate of lime, alumina, 

 iron, sulphate, and muriate of potash. 

 Weak acids soften bird-lime, and partly 

 dissolve it ; strong acids act with more 

 violence. Sulphuric acid renders it black ; 

 and when lime is added to the solution, 

 acetic acid and ammonia separate. Nitric 

 acid, cold, has little effect ; but when as- 

 sisted by heat, it dissolves the bird-lime ; 

 and the solution, when evaporated, leaves 

 behind it a hard brittle mass. By treat- 

 ing this mass with nitric acid, anew solu- 

 tion may be obtained, which by evapora- 

 tion, yields malic and oxalic acids, and a 

 yellow matter which possesses several of 

 the properties of wax. Cold muriatic 

 acid does not act on bird-lime ; hot mu- 

 riatic acid renders it black. Bird-lime, 

 when treated with oxymuriatic acid, be- 

 comes white, and is divided into hard, 

 compact masses, having unaltered bird- 

 lime in their centre. This white sub- 

 stance may be pulverized ; it is insoluble 

 in water ; does not melt when heated : 

 and when treated with nitric acid,it nei- 

 ther becomes yellow, nor does it yield re- 

 sin. Acetic acid softens bird-lime, and 

 dissolves a certain portion of it. The li- 

 quid acquires a yellow colour. Its taste 

 is insipid. When carbonate of potash is 

 dropped into this solution, no precipitate 

 falls. By evaporation it yields a resinous- 

 like substance. Some of the metallic ox- 

 ides are reduced when heuted with bird- 

 lime. Litharge combines with it, and 

 forms a kind of plaster. Alcohol, of the 

 specific gravity 0.817, dissolves bird-lime 

 at a boiling heat. On cooling, it lets fall 

 a yellow matter, similar to wax. The fil- 

 tered liquid is bitter, nauseous, and acid. 

 Water precipitates a substance similar to 

 resin. Sulphuric ether dissolves bird-lime 

 readily and in great abundance. The so- 

 lution is greenish. When mixed with wa- 

 ter, an oily substance separates, which 

 has some resemblance to linseed oil. 

 When evaporated, a greasy substance is 

 obtained, having a yellow colour, and the 

 softness of wax. 



BIRDS' nests, in cookery, the nest of a 

 small Indian swallow, very delicately 

 tasted, and fequently mixed among 

 soups. On the sea coasts of China, at cer- 

 tain seasons of the year, there are seen 



