PHY 



OR, BOTANICAL DICTIONARY. 



PHY 



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and Birch trees, and in the woody fibres of several plants. 

 6. Albumen dissolves only in cold water. It is hardened by 

 boiling water, and, when distilled, sets loose volatile alka- 

 line salt. It is found in the farinaceous seeds of several 

 plants, in those of the Tetradynamia class, in the juice of 

 White Cabbage, in the root of Scilla maritima, &c. 7. The 

 extractive principle when separated from other constituents 

 with which it is combined in the plants, is a solid bitter 

 rough-tasted substance, which may be dissolved at any tem- 

 perature in water or spirit of wine. It discovers itself chiefly 

 by its great affinity for oxygen, which it rapidly absorbs, 

 thus becoming insoluble in water. It is found in almost 

 every plant without exception, never pure, but combined 

 with mucilage, sugar, resin, acids, &c. &c. In modern 

 times only it has been properly distinguished. Formerly it 

 was confounded with vegetable mucilage, or, when by being 

 combined with oxygen it had become insoluble in water, it 

 was considered as resin. The name, Soapy Matter, which 

 is sometimes given to this substance, is improper, and often 

 leads to very erroneous ideas. 8. Tannin is a solid friable 

 brown substance of a very astringent taste, and has some 

 resemblance to the extractive principle, but differs in this 

 respect, that it transforms animal jelly int0 a viscid sub- 

 stance insoluble in water and proof against corruption. On 

 this is founded a property which plants, containing this mat- 

 ter, possess, of converting the gelatinous skin of animals into 

 insoluble leather. Tannin also precipitates in various co- 

 lours the metals which have been dissolved in acids. It pre- 

 cipitates iron black, by which means common ink is ob- 

 tained. It is always found combined with gallic acid in the 

 barks of many trees, in many kinds of wood and roots, in the 

 leaves of some plants, and in the excrescences occasioned by 

 insects. It abounds chiefly in Quercus Robur and peduncu- 

 lata, Rhus typhinum, in the bark of Salix, Alnus, Fraxinus, 

 and Cinchona, in the nut-shell of the Juglans regia, in the 

 roots of Tormentilla, Potentilla, Fragraria, Polygonum Bis- 

 torta, &c. &c. 9. Fixed oil is an inflammable tasteless fluid 

 without smell, and is not soluble either in water or spirit of 

 wine. Combined with caustic alkaline salt, it becomes soap, 

 which is soluble in water : it is destroyed by the heat of boil- 

 ing water. It consists principally of hydrogen and carbon, 

 and is found almost exclusively in the seeds and fruits of 

 vegetables ; for example, Amygdalus communis, Linum usita- 

 tissimum, &c. &c. Cyperus tsculentus is the only plant 

 hitherto discovered, the root of which yields fixed oil. 

 10. Wax is a vegetable oil condensed by oxygen, and is 

 discovered in the fruits of Laurus nobilis, Myrica cerifera, 

 Tomex sebifera, and in the pollen of almost all plants. It is 

 from this that bees prepare their wax. 1 1 . Resin is a brit- 

 tle solid substance, which, though insoluble in water, may 

 be dissolved in oil and spirit of wine. It is melted with 

 slight heat, and burns with the application of flame. It is 

 found in a great many plants, as in the Pinus, Juniperus, 

 &c. ; combined with real volatile oil, it is called Balsam. 

 Some allege that the name Balsam should be given only to 

 such resins as contain benzole acid. 12. Caoutchouc is a 

 very elastic substance, not unlike leather, and is soluble only 

 in ether. It proceeds like milky juice from the trees in the 

 torrid zone; for example, Suphonia Cahucu, Commiphora 

 Madagascariensis, &c. It is found in the berries of Viscum 

 album. It is probably a constituent of several gum-resins. 

 13. Gum-resins, mucus-resins, are to be considered not as 

 mere mixtures of mucus or gum and resin, but as possessing 

 a compound nature, and as properly forming the more im- 

 mediate constituents of vegetables. T ne y fl w like milk 

 from several plants. Some approach to the nature of oxi- 



dized extractive. They also contain resin, sugar, mucus, 

 caoutchouc, and volatile oil. Several species of gum used 

 by apothecaries belong to this class ; for example, Assafa - 

 tida, Sagapoenum, Ammoniacum, Galbanum, &c. &c. 14. 

 Volatile oil is an inflammable volatile liquid which, wholly 

 dissolves in spirit of wine, and partially in water. It has a 

 remarkable taste and smell, and may be distilled over without 

 being destroyed. It is found in a great, number of plants, 

 and may be contained in all their parts, roots, wood, rinds', 

 leaves, flowers, fruits, principally, however, in the pulp of 

 fruits. Although volatile oils all agree with one another HI 

 their essential qualities, they differ considerably in regard i : > 

 colour, smell, taste, consistence, and weight. In progress of 

 time they condense, and assume the appearance of resins, by 

 being combined with oxygen. 15. Camphor is a solid white- 

 coloured substance, friable, and very inflammable. It has a 

 peculiar smell and taste, and is extremely volatile. It exists 

 chiefly in all the parts of the Laurus Camphora, as also in 

 many species of Laurus Cinnamomum, &c. Some volatile 

 oils also contain it; for example, those of Lavandula Spica, 

 Origanum Majorana, Salvia officinalis, &c. 16. The bitter 

 principle is found in those plants which in a fresh condition 

 burn the mouth and blister the skin, but which lose this 

 property when dried; for example, Scilla maritima, Arum 

 maculatum, Helleborus niger, Chelidonium majus, Digitalis 

 purpurea, most of the species of Ranunculus, &c. &c. It is 

 sometimes combined with volatile oils; for example, Coch- 

 learia armoracia, officinalis, Sinapis alba, nigra, &c. 17. 

 The narcotic principle is considered as the original cause of 

 the bad effects which the fruit of several plants produces on 

 the brain, in diminishing the power of sensation and motion, 

 and, when taken in large doses, by inducing sleep, and in 

 the end occasioning vertigo, stupefaction, and even death. 

 To this description belong Papaver somniferum, Hyoscyamus 

 niger, Datura Stramonium, Prunus Laurocerasus, Atropa 

 Belladonna, &c. 18. Fibrin must necessarily be considered 

 as a proper constituent of vegetables, as its chemical process 

 in plants is different from what it is in all other bodies. It 

 is quite insoluble, has neither taste nor smell, and, beside 

 the three necessary elements, also contains azote. 



" As the life of animals depends on external warmth, so 

 likewise plants need a certain degree of it. Plants of warm 

 countries require more of it than those which belong to cold 

 ones. These are facts which need no further demonstration. 

 But whether plants, like animals, have a fixed and peculiar 

 degree of heat, is a question which must now be answered. 

 We find that trees or shrubs, in cold climates, if they grow 

 wild, endure the greatest cold without harm. As soon as the 

 warmth of spring commences, they evolve their buds, and 

 apparently suffer no bad effects from the cold, though their 

 stem and branches are full of moisture. If in a strong frost 

 we put vessels with water close to such a tree, we shall find 

 that the water is converted into ice, but that the tree retains 

 its sap unfrozen, and remains quite unhurt. The case is dif- 

 ferent in plants of warm and hot regions. The sap of these 

 plants congeals at the least degree of cold, andthe plants 

 decay. Thus there appears a remarkable difference between 

 the plants of cold and those of hot climates. As long as 

 plants livs, and possess sufficient vital power to resist cold, 

 their sap will not congeal. But after the buds have been 

 forced out by the warm weather of spring, they will, when 

 exposed to cold evenings, be observed to congeal. We find, 

 likewise, that dead or diseased branches are more liable to 

 be frost-bitten than living and sound ones, and (hat branches, 

 by their sap being congealed, are destroyed. The Birch and 

 some other pJants, it is well known, often have their roots 



