What is bezoar? Please give me the best explanation, thank you!

This product is a dry gallstone of BostaurusdomesticusGmelin, a cattle animal. When slaughtering cattle, if bezoar is found, filter bile, take out bezoar, remove outer membrane and dry in the shade. The English name is calculus bovis. Properties: Most products are oval, spherical, triangular or square, with different sizes, with a diameter of 0.6 ~ 3 (4.5) cm, and a few are tubular or fragmented. The surface is yellow-red to brownish-yellow, and some surfaces are hung with a layer of black shiny film, commonly known as "black gold coat", some are rough, with warty protrusions, and some have turtle cracks. Light weight, crisp texture, easy delamination and peeling, golden yellow section, thin concentric layer, and some with white heart. It smells fragrant, tastes bitter first and then sweet, and has a cool feeling. It is fragile when chewed and does not stick to teeth. Identification (1) Take a small amount of this product, mix it with clear water, and apply it on nails, which can dye nails yellow, commonly known as "hanging nails". (2) Take a little of this product, put it into tablets with chloral hydrate test solution, and observe it under the microscope without heating: irregular lumps are composed of most small brown or brownish red particles. When encountering chloral hydrate solution, the pigment quickly dissolves and becomes bright golden yellow, and turns green after being left for a long time. (3) Take 65438+/-00 mg of this product powder, add 20ml of chloroform, ultrasonic for 30 minutes, filter, evaporate the filtrate, and add 65438+/-0 ml of ethanol to dissolve the residue as the test solution. In addition, cholic acid and deoxycholic acid were used as reference substances, and ethanol was added to prepare a mixed solution containing 2mg per kloc-0/ml as reference substance solution. According to the thin-layer chromatography test (Appendix ⅵ b), absorb 2μl of each of the above two solutions, respectively spot them on the same silica gel G thin-layer plate, develop them with isooctane-ethyl acetate-glacial acetic acid (15:7:5) as the developing agent, take them out, dry them, spray them with 10% sulfuric acid ethanol solution, and spray them on/kloc. In the chromatogram of the test sample, two fluorescent spots with the same color appear in the position corresponding to the chromatogram of the control sample. According to the moisture determination method (appendix ⅸ h first method), the moisture content shall not exceed 9.0%. Determination of cholic acid: Take about 0.2g of fine powder of this product, weigh it accurately, put it in a conical flask with a stopper, add 50ml of methanol accurately, plug it tightly, weigh it, perform ultrasonic treatment for 30min, weigh it again, make up the weightlessness with methanol, shake it evenly, filter it, accurately measure 25ml of continuous filtrate, evaporate it to dryness, add 20% sodium hydroxide solution 10ml to the residue, and heat and reflux it for 2h. Add dilute hydrochloric acid 19ml to adjust pH to acidity, and extract with ethyl acetate for 4 times (25ml, 25ml, 20ml, 20ml). Each time, the ethyl acetate solution was filtered through the same absorbent cotton covered with a small amount of anhydrous sodium sulfate, and the extracts were combined and evaporated to dryness. Dissolve the residue with methanol and transfer to a 10ml volumetric flask. Add methanol to the balance and shake well to obtain the test solution. In addition, the cholic acid reference substance dried to constant weight at 105℃ was accurately weighed, and methanol was added to make a solution containing 0.48mg per 1ml as the reference substance solution. According to the thin-layer chromatography test (Appendix ⅵ b), accurately suck 2μl of test solution and 3μl of reference solution 1μl respectively, and spread them on the same silica gel G thin-layer plate with isooctane-butyl acetate-glacial acetic acid-formic acid (8:4:2: 1) as the developing agent to/kloc-0. Heat it at 105℃ until the spots are clear, take it out, cover the thin-layer plate with a glass plate of the same size, fix it around with adhesive tape, and scan it with thin-layer chromatography (appendix ⅵ b thin-layer scanning method), wavelength: λ.