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CONSIDERATION OF CARBON COMPOUNDS. 



Glycogen, C 6 H 1() 5 . Found exclusively in animals; it occurs in 

 the liver, the white blood-corpuscles, in many embryonic tissues, 

 and in muscular tissue. Pure glycogen is a white, starch-like, 

 amorphous substance, soluble in water, insoluble in alcohol; by 

 the action of diluted acids it is converted into glucose. 



Glucosides. This term is applied to a group of substances 

 (chiefly of vegetable origin), which by the action of acids, 

 alkalies, or ferments suffer decomposition in such a manner 

 that one . of the products formed is grape-sugar. Glucosides 

 may, therefore, be looked upon as compound sugars, or sugar in 

 combination with various other substances. The following is a 

 list of the more important glucosides, giving also the composi- 

 tion and the source whence they are obtained: 



Amygdalin, C 20 H 27 NO U , Bitter almonds, etc. 



Arbutin, C 25 H 34 M , Arbutus uva ursa 



Cathartic acid, C 180 H 192 N 4 SO 82 ? Senna. 



Carminic acid, ? Cochineal. 



Colocynthin, C^H^Ojj? Colocynthis. 



Digitalin, C^H^O^? Digitalis. 



Elaterin, C 26 H 28 O 5 , Cucumber fruit. 



Gentiopicrin, C^H^O^, Root of gentiana. 



Glycyrrhizin, C^H^O^ Liquorice root. 



Helleborin, C 36 H 42 O 6 , Root of hellebore. 



Indican, ? Indigo plant. 



Jalapin, C^H^O,^ Jalap resin. 



Myronic acid, C, H 19 NS 2 O 10 , Seeds of black mustard. 



Picrotoxin, C 9 H 10 O 4 , Cocculus indicus. 



Salicin,' C 13 H 18 O 7 , Bark of willow. 



Santonin, C lft H 18 3 , Wormseed. 



Scammonin, ^34H 56 O 16 , Resin scammony. 



Solanin, ? Various species of solatium. 



Tannins, O ]4 H 10 O 9 , In many barks, leaves, etc. 



Some of the above glucosides, such as amygdalin, salicin, 

 tannin, have been mentioned before. 



Santonin, Santoninum, C 15 H 81 3 = 246. Santonin is the active 

 principle of wormseed, the unexpanded flower-heads of Arte- 

 misia. It crystallizes in colorless prisms, which turn yellow on 

 exposure to light; it is but sparingly soluble in water, more 

 soluble in alcohol and ether; it has distinct acid properties, com- 

 bining with strong bases, as, for instance, with sodium hydrate, 

 forming the officinal santoninate of sodium, 2(NaC 15 H 19 O 4 ).7H 2 O. 



