152 CONTENTS OF THE INTESTINAL CANAL. 



composition presents no peculiar interest in a physiologico- 

 chemical point of view. 



The concretions termed bezoars, which have recently been 

 examined with much care by Merklein and Wohler* and by 

 Taylor, f are of far more importance and interest. The former 

 analysts found that bezoars might be classified according to their 

 chemical nature, (1) into such as consist of phosphate of lime 

 and phosphate of ammonia and magnesia; (2) into such as consist 

 of lithof elite acid; and (3) into those formed of ellagic or 

 bezoardic acid. It is to the last class and its consituents that the 

 above-named chemists have especially devoted their attention. 



The bezoars consisting of ellagic acid, which are the true oriental 

 bezoars, have a dark olive-green and sometimes a marbled brownish 

 colour, an oval form, a smooth surface, a concentric laminated 

 structure, and splinter when broken ; in their interior they have 

 a foreign nucleus ; their size varies from that of a bean to that of 

 a small hen^s egg. On being heated, they carbonise without fusing, 

 and become covered with glistening yellow crystals. Like Taylor 

 (see vol. i. p. 118), they found the bezoardic acid to be identical 

 with the substance known as ellagic acid, but they assigned to it a 

 somewhat different composition from that determined by Pelouze, 

 their formula being HO + C 14 H 2 O 7 -f 2 Aq, while that of the 

 French chemist was C 7 H 2 O 4 . This acid possesses the peculiarity 

 that in its potash-salts it oxidises very rapidly when free access of 

 atmospheric air is allowed, so that amongst other products of 

 decomposition, a new acid, glauco-melanic acid (= C 12 H 2 O 6 ), is 

 produced. It is worthy of remark that the last named acid, if its 

 potash- salt be treated with water or be decomposed by hydro- 

 chloric acid, again yields ellagic acid. 



The formation of ellagic from gallic acid during the act of 

 digestion in animals yielding bezoars, may be explained by our 

 assuming that two atoms of gallic acid lose three atoms of water 

 and assimilate an atom of oxygen, as is shown in the formula, 

 C u H 6 O 10 -3 HO + O = C 14 " H 2 O 7 . HO. 



Taylor has also carefully examined the intestinal concretions 

 known as bezoars. He divides them into (1) calculi consisting of 

 animal hairs; (2) of vegetable hairs; (3) of ellagic acid; (4) of 

 lithofellic acid; (5) of phosphate of ammonia and magnesia; (6) 

 of diphosphate of magnesia; (7) of diphosphate of lime; (8) of 

 oxalate of lime ; (9) of ambergris. 



* Ann. d. Ch. u. Pharm. Bd. 55, S. 129-143. 

 t Phil. Mag. Vol. 28, pp. 44 and 192. 



