GLYCERINE 



<;LVI'T()I)ON 



261 



ami in chloroform. It* specific gravity w T27. 

 It .mirklv cooled down, glycerine does not crystal 

 Ij-,-, l,ui -M.lidilies at 40" ('. into u gum lik(1 "" IMH - 

 In tin- \\inter <>f 1H<>7 it was discovered lli.-U some 

 -l\. line which wii-s living shipped to England had 

 i into ;i s.ili<l crvstulline mass; till then 

 e.l\cerine was hclicveil to l>e niicr\ stallisaUe. 



At 100" it is slightly volntile, hut if distilled alone 



the greater pal I of it become* decomposed ; il may, 



however, ! distilled \\ithout alteration in a mr- 

 lent ui raperheated steam. Hy this means Wilson 

 Micceeded in is.-Vl in separating; heated fats into 

 line an.l tin- arid with which it was pre- 

 viously in combination; the glycerine is thus 

 .ilitain'ed in a high state of concentration as a 

 colourless, -yrupy liquid, which can be thus pre- 

 pared in unlimited quantity. 

 tilvceiine occurs ready formed in a few fats (as, 

 .dd palm oil), and, according to Pasteur. is 

 eontained in all fermented liquors, and especially 

 in wine. It is a product of the saponitication of 

 the various fats. See SoAP. 



Glycerine is a triatomie alcohol i.e. it is derived 

 from' three molecules of water hy replacing three 

 atoms of hydrogen hy the triatomie radical C. t Hr,; 

 c.r it may I'M- considered -a compound of C 3 H S with 

 three nmlecules of hydroxyl, OH and may he 

 represented l>v the formula C 3 H 8 (OH) 3 ; and in 

 the animal and many vegetahle fats, the three 

 molecules of hydroxyf are replaced by three mole- 

 cules of the anhydrous fatty acid. In the saponiti- 

 cuiion of these fats that is to say, when they are 

 treated with potash, soda, or oxide of lead, or 

 under the influence of superheated steam the fatty 

 acid separates from C 3 H S , which assimilates three 

 tnolecnfea of hydroxyl and becomes glycerine. 

 (.lycerine forms' sol ulile compounds with baryta, 

 str.mtia, and lime; and it dissolves oxide of lead 

 and numerous salts. It is found that glycerine is 

 < '.avertible into a true fermentable sugar when 

 treated with a mixture of potassium bichromate 

 and sulphuric acid, or with potassium permanganate 

 in presence of sunlight. 



We have already referred to the best mode 

 i Wilson's process) of obtaining glycerine on a 

 large scale ; the usual method of obtaining it on a 

 small scale is from olive-oil, which is saponified by 

 treating it with an equal weight of litharge ( lead 

 oxide). This is mixed with water, and added to 

 the oil, with which it is boiled till the saponitica- 

 tion is complete. The glycerine is dissolved by 

 the water, and is easily separated from the in- 

 soluble lead-plaster (a mixture of oleate and pal- 

 mitate of lead). Any traces of lead are removed 

 by sulphuretted hydrogen, and the water is 

 expelled in i-nrnn, as the glycerine would turn 

 brown in the open air. 



The uses of glycerine are numerous. In medi 

 cine it U employed as a local application ir 

 di-eases of the skin and of the ear ; it is used as a 

 solvent for many drugs; and is taken internally 

 for the same purposes as cod-liver oil. It is a 

 valuable preservative fluid for small and delicate 

 anatomical preparations, and it has been appliec 

 to the preservation of meat. It is used in per 

 funiery, in calico-printing, and in the preparation 

 of leather. It is used by the wine-dealer to 

 ' improve ' the quality of wine, and by the brewer 

 as it is said, to impart keeping power to beer 

 Very large ijuantitie- of glycerine are required fo 

 the production of Nitro-glycerine (q.v.) and othe 

 explosives. It has been added to the water in gas 

 meters with the view of preventing it from free/ing 

 It is used in the manufacture of copying-ink, am 

 i~ of ^'i-neral appl icat ion where a lubricating agen 

 is required. 



Like the alcohols in general, to which clas 

 glycerine belongs, it forms several classes or series 



f derivative!*, the most important of which are 

 to combination* with acids, which are analogous 

 a then r.imposition to the \ariouH fata and oil*, 

 lee Roijcoe and Schorlemniei'H Treatise on Chem- 

 ,//</, and Sehorlemmei'n Maniml of the C'hemutry 

 jft/ie Cnrlinii t 'inti/xiunds. 

 Cilvcocoll, or A vino ACETIC ACID, CH^NH,) 

 <),|f, was first prepared by liroconnot in 1820, 

 M-ing obtained among the products of the action of 

 nlphuric acid on glue, ami neehed from him the 

 lame Kiu-n- ill i/i/ntine, on account of its sweet 

 taste. It is a product of various processes of 

 decom position ot animal matters. Glycocoll in 

 very soluble in water, the solution having no effect 

 on vegetable colours, but it is insoluble in alcohol. 

 vJlycocoll combines lioth w ith acids and bases, and 

 the compounds in both cases are soluble and 

 irystallisable. 



Glycogen, C, a H l O Im H,O, sometimes called 

 inimal starch, was discovered by Claude Bernard 

 in the human liver as well as that of graminivoioiiH 

 inimals. It has l>een shown to exist very widely 

 diffused throughout the animal kingdom, and 

 appears to be an essential accompaniment of cel- 

 lular growth, occurring in large quantities in the 

 Fujtus. It occurs also in blood and muscular tissue. 

 It is found in mollusca, dried oysters being said to 

 contain as much as 9'5 per cent. (Jlvcogen has 

 also been detected in the vegetable kingdom, in 

 moulds and other fungi. Its uses in the animal 

 economy are noticed in the article LIVER. 



lycol is the type of a class of artificial com- 

 pounds, whose existence was inferred, and after- 

 wards discovered, by Wurtz. In their chemical 

 relation and properties they form an intermediate 

 series between the monatomic alcohols, of which 

 common alcohol is the type, on the one hand, and the 

 triatomie alcohols, a class of bodies of which ordi- 

 nary glycerine is the type, on the other. The name 

 of glycol, formed from' the first syllable of glycerine 

 and the last of alcohol, has been given to express 

 this relation. The glycols are accordingly termed 

 diatomic alcohols. Ordinary glycol is formed from 

 ethylen, CLH 4 , and hence may be called ethyl- 

 glycol, to distinguish it from propyl -glycol, which 

 is formed from propylen, C 3 rL, from butyl-glycol, 

 which is formed from butylen, C 4 H 8 , or from amyl- 

 glycol, which is formed from amylen, CjH.o. Glycol 

 & a colourless, slightly viscid fluid, with a sweet 

 taste, and its composition is expressed by the 

 formula C 2 H 4 (OH) 2 . See Schorlemmer's Manual 

 of the Chemistry of the Carbon Compounds. 



Glycose. See SUGAR. 



4il> cosinis. a genus of Aurantiacety, trees of 

 the East Indies. The fruit of (J. citri folia is 

 delicious. 



Glyptodon (Gr., 'engraved tooth'), a gigantic 

 fossil animal belonging, like the Megatherium 

 (q.v.) and the My lotion (q.v.), to the Edentata, 

 but of the family of the Dasypodidffi or Armadillos. 



Glyptodon olavipes. 



It is found in the post-tertiary deposits of the 

 pampas of South America, and four species have 

 been described. The back and sides of the creature 

 were covered with a carapace of thick, nearly hexa- 



