194.' Mr. T. Taylor oil so?ne 



Resino-bezoardic acid calculi are usually of an oval figure. 

 Their external surface is smooth and polished, and has gene- 

 rally a greenish yellow, green, or a light brown colour. They 

 are made up of thin concentric layers, which are frequently 

 of a deeper tint than the exterior. In the centre of the cal- 

 culus some foreign body is invariably found which forms the 

 nucleus. These calculi are exceedingly brittle ; the fracture 

 is conchoidal, and has a resinous lustre. They vary con- 

 siderably in size, but are usually larger than the ellagic acid 

 species. One specimen in the Museum measures nearly ten 

 inches in circumference, They melt like resin in the flame 

 of a candle, and when more highly heated, give off white va- 

 pours, which have an aromatic odour, catch fire, burn with a 

 brilliant flame, and leave behind a small shining carbonaceous 

 ash. 



Resino-bezoardic acid calculi readily dissolve in alcohol, 

 with the exception of a small quantity of flocculent matter. 

 The alcoholic solution varies in colour in different calculi, but 

 is usually of a red or greenish-red tint. The solution gradu- 

 ally deposits small crystals, which, when examined by the 

 microscope, are seen to consist of low six-sided prisms with 

 flattened extremities. When the alcoholic solution is mixed 

 with water the resin is thrown down. The precipitate appears 

 under the microscope in the form of small crystalline tufts. 



Digested in solution of potass these calculi readily dissolve, 

 the solution is of a brownish green colour, and when neutral- 

 ized by an acid, a thick curdy precipitate is produced, which 

 by agitation adheres together, and while warm may be kneaded 

 between the fingers or drawn into threads like cobbler's-wax. 

 The viscidity of this precipitate is owing to another resinous 

 matter which the calculi contain ; for the pure resino-bezoardic 

 acid similarly treated forms an amorphous precipitate which 

 cannot be made to adhere together. They dissolve in solu- 

 tions of ammonia and its carbonate. In concentrated sulphuric 

 acid they also dissolve. The solution is of a red colour, and 

 is rendered turbid by the addition of water. The precipitate 

 is not crystalline, like that from its solution in alcohol, but 

 consists of minute transparent yellow particles. Nitric acid 

 acts with energy upon these calculi, nitrous acid is evolved, 

 and a light red solution is formed, which quickly becomes 

 yellow. 



Analysis. 



About 400 grains were reduced to a fine powder, mixed 

 with distilled water, and subjected to distillation in a glass 

 retort until about two ounces had passed over. The distilled 



