524 GENERAL ANATOMY. 



culi, cholelithi. They are found most often in- 'the gall blad- 

 der; sometimes in the duct us choledochus or the cystic, or 

 hepatic ducts; or in the intestinal canal, and rarely in the 

 roots of the hepatic canal within the liver. The number and 

 size of these calculi vary extremely: from one to several thou- 

 sand have been found in the same gall bladder, from the size 

 of a pullet's egg to that of a millet seed; their colour varies 

 from white to yellow, brown, and black; their surface is 

 rounded or polyhedral, polished or rugose; their consistence 

 varies much; their specific gravity is from 0.20 to 0.35. They 

 are divided, according to Walter, into three kinds: striated or 

 radiated, striati^ lamellated, lamellati, and provided with a 

 rind, cordicati. In the human species these calculi are* formed 

 of cholesterine, of the yellow matter of the bile, and some- 

 times of a little picromel. 



Urinary calculi,* urolithi, are found in the pelvis of the 

 kidney, in the ureter, in the mouth of this canal, in the blad- 

 der, in the urethra, in the prepuce, in the loculi of the bladder, 

 in the ducts of the prostate,, and in accidental urinary cavities 

 and passages. 



The calculi of the pelvis and calices of the kidney, mould 

 themselves in these cavities, when they increase in this place 

 and become ramose like a branch of coral. 



Calculi of the bladder are the most common; sometimes, 

 and it is so ordinarily, there is only one in the bladder, some- 

 times there are several; more than a hundred have been seen. 

 Their size and their weight vary from that of a grain of wheat 

 to that of an infant's head, and to more than six pounds in 

 weight. Their form is round, obround, tetrahedral, cunei- 

 form, or cubic, &c. 



Their surface is smooth, rugose, or mamillary; their colour 

 apd consistence are very variable. They have always a nu- 

 cleus, formed, either of a gravel stone descended from the 

 pelvis of the kidney,' a clot of blood, a flocculus of mucus, or 

 a foreign body. 



*Fourcroy et Vajiquelin, Mem. de Pinst. .Nat., torn. iv. Wollaston, 

 Phibs. Trans., ann. 1797, &c. 



