178 LEGUMINOS^. 



it swells, and in the course of some hours disintegrates so that it can be 

 diffused through the liquid. So great is its power of absorbing water 

 that even with 50 times its weight, it forms a thick mucilage. If one 

 part of tragacanth is shaken with 100 parts of Avater and the liquid 

 hltered, a neutral solution may be obtained which yields an abundant 

 precipitate with acetate of lead, and mixes clearly with a concentrated 

 solution of ferric chloride or of borax,— in these respects differing frum 

 a solution of gum arable. On the other hand, it agrees with the latter 

 in that it is thrown down as a transparent jelly by alcohol, and rendered 

 turbid by oxalate of ammonium. The residue on the filter is a slightly 

 turbid, slimy, non-adhesive mucilage, which when dried forms a very 

 coherent mass. It has received the name of Bassorin, Tragantkin or 

 Adraganthin, and agrees Avith the formula C^-m-^0^\ 



Tragacanth is readily soluble in alkaline liquids, even in ammonia 

 water and at the same time assumes a yellow colour; heated with 

 ammonia in a sealed tube at 90° C. it blackens. 



Ihe drug loses by drying about 14 per cent, of water, which it 

 absorbs again on exposure to the air. Pure flake trao-acanth incinerated 

 leaves 3 per cent, of ash. 



Commerce— Tragacanth is shipped from Constantinople, Smyrna 

 and the Persian Gulf The annual export of the gum from Smyrna has 

 been recently stated^ to be 4,500 quintals, value 675,000 Anstrian 

 norms (ib7,o00} ; and the demand to be always increasing. 



Uses— Though tragacanth is devoid of active properties, it is a very 

 uselul addition to many medicines. Diffused in water it acts as a 

 (lemulcent, and is also convenient for the suspension of a heavy powder 

 in a mixture. It is an important ingredient for imparting finnness to 

 lozenges and pill masses. 



Adulteration— The fine quantities consisting of large distinct pieces 

 are not liable to adulteration, but the small and the inferior kinds are 

 often sophisticated. At Smyrna, tragacanth is mixed with gums termed 

 le^j^ectiyely Mosul and Caramania Gum. The former appears to be 

 simply very inferior tragacanth ; the latter which is sometimes called u^ 

 the London market Hog Gum Tragacanth or Bassora Gam,' is said to 

 be the exudation of almond and plum trees. It occurs in noduai 

 masses of a waxy lustre and dull brown hue, which immersed iu water 

 fwi^r^T'"^ ^"'^^ "" voluminous white mass. - To render this g"n 

 W. ? 1 adulteration, the lumps are broken into small anguja 

 ^a^ments, the size of which is adjusted to the sort of tragacanth with 

 I V ■. '^ ^'? *^ ^^ "^^^^e^i- A« the Caramania Gum is somewhat 

 .ZrJiV' f '^'^l^ '^'^^^^^ '' ^y ^^^^ l<^^d, previous to mixing it with 



^maU LeaJ ovFktke, or with the Ve^^.icelli gum. , , 



fr.cmf T } ,e-?^™ination the fraud is easily detected, angular 

 ead nT. r* ^'\"° i'^'^r^^^- *^ ^"y true tragacanth. The presence oi 

 moLn;^ vl '?^,^^^^ I^^'^^^d by .shaking suspected fragments for » 

 meS alf ^^^^"^^ °^^^"^^ ^«H which will dissolve any caiWj 

 ieagents. ""'"^ ^ '"^"^^*^^ ^^^^^ ^^7 ^^ *°«t^^^ b>' ^^'' ' 



143.^' '''" ^'^'''''' ''^"'y^""' Wien, 1873. ^ It is sometimes sl.ippc<i from B.r-rah. 



