CATECHU. 243 



Description — Cutch is imported in mats, bags, or boxes. It is a 

 dark brown, extractiform substance, hard and brittle on the surface of 

 the mass, but soft and tenacious within, at least when newly imported. 

 The large leaf of Dipterocarjm.s tuherculatus Roxb., the Ein or Enghen 

 of the Burmese, is often placed outside the blocks of extract. 



Cutch when dry breaks easily, showing a shining but bubbly and 

 slightly granular fracture. \VTien it is soft and is pulled out into a thin 

 film, it is seen to be translucent, gi"anular and of a bright orange-brown. 

 When further moistened and examined under the microscope, it exhibits 

 an abundance of minute acicular crystals, precisely as seen in gambler. 

 We have observed the same in numerous samples of the dry drug when 

 rendered pulpy by the addition of water, or moistened with glycerin 

 and viewed by polarized light. 



The pale cutch referred to as manufactured in the north of India, is 

 in the fonn of irregular fragments of a cake an inch or more thick, which 

 has a laminated structure and appears to have been deposited in a round- 

 bottomed vessel. It is a porous, opaque, earthly-looking substance of 

 a pale pinkish brown, light, and easily broken. Under the microscope 

 it is seen to be a mass of needle-shaped crystals exactly like gambler, 

 with which in all essential points it corresponds. We have received 

 from India the same kind of cutch made into little round cakes like 

 lozenges, with apparently no addition. The taste of cutch is astringent, 

 followed by a sensation of sweetness by no means disagreeable. 



Chemical Composition — Extractiform cutch, such as that of Pegu, 

 which is the only sort common in Europe, when immersed in cold water 

 turns whitish, softens and disintegrates, a small proportion of it dis- 

 solving and forming a deep brown solution. The insoluble part i.-^ 

 Catechin in minute acicular crystals. If a little of the thick chocolate- 

 like liquid made by macerating cutch in water, is heated to the boiling 

 point, it is rendered quite transparent (mechanical impurities being 

 absent), but becomes turbid on cooling. Ferric chloride forms with this 

 solution a dark green precipitate, immediately changing to purple if 

 common water or a trace of free alkali be used. 



Ether extracts from cutch, catechin. This substance has been in- 

 vestigated by many chemists, but as yet with discrepant results. It 

 agrees, according to Etti (1877), with the formula C^^ff^O^ when dried 

 at 80° C. By gently heating catechin, Catechutantiic acid, C^H**0'^ 

 is produced : 



2(C"ff'0') — OW = C^H**0'^ 



This is an undoubted acid, readUy soluble in water, of decidedly tannin or 

 properties, precipitating also the alkaloids and albumin. Catechutannic 

 acid being the first anhydride of catechin, there are several more sub- 

 stances of that class; one of them is called Catechuretin. This blackish 

 brown almost insoluble substance is obtained by heating catechin with 

 concentrated hydrochloric acid at ISO'' : 



Catechin, by melting it with caustic potash, affords Protocatechuic acid, 

 C6H\OH)2COOH, and Phloroglucin, C«H'(OH)^ : 



Qi9jj,8Q8_,_9 Qjjo ^ 4 jj . (jH-'O^ • 2 CTT*'0^ 



