84 SURGERY. 



of the symptoms are simulated by other diseases, such as stricture of 

 the urethra, enlarged prostate, irritable bladder, &c. The rectum sym- 

 pathizes, especially in children, and hemorrhoids or prolapsus ani 

 are apt to occur. Stones vary in their form, size, colour, consis- 

 tence, and chemical composition ; some are rough on their surface, 

 others smooth ; they are more frequently of an oval shape. The size 

 may be that of a pea, or that of a goose-egg. The most common 

 colour is a light brown ; some, however, are nearly white, others 

 nearly black. Some are soft and friable, and crumble easily ; others 

 are flinty, and require great force to fracture them. 



They are most generally composed of lithic or uric acid, lithate 

 of ammonia, phosphate of Ume and magnesia, oxalate of lime, and 

 carbonate of lime. The lithic acid stones are perhaps the most com- 

 mon : they are oval, flattened, of a fawn-colour, and consist of con- 

 centric laminae ; the phosphatic stones are light-coloured and friable. 

 The oxalate of lime forms the mulberry calculus, which is the hardest 

 stone, of a very dark colour and a very rough surface. The numter 

 existing in the bladder at once, may vary from one to several 

 hundred. 



The formation of stone is consequent upon a derangement of 

 health, deficiency of exercise, indulgence in animal food, defective 

 condition of the skin, and dyspepsia. It is also dependent upon 

 climate, age, locality, and hereditary influences. The immediate 

 cause in every case cannot be discovered ; some suppose that the 

 character of the water drank influences its production. Stones are 

 sometimes encysted in the prostate gland and urethra. 



Treatmejit. — Gravel may be prevented or mitigated by attention 

 to the skin and digestion, the use of acids or alkalies, dependent upon 

 the diathesis of the patient manifesting the disease ; but, after stoiw 

 has been lodged in the bladder, it cannot be removed by medicines : 

 surgical means must be resorted to. 



Sounding. — This requires great tact and care in its performance, 

 and must only be attempted when the condition of the patient is most 

 favourable ; if performed immediately after a journey, or during a fit 

 of the gravel, the consequences might be serious. A sound is a 

 solid steel instrument, resembling a catheter in shape, but having its 

 curvature much nearer the extremity, and a broad flattened handle. 

 The patient should be placed in a recumbent position, and the urine 

 retained in the bladder for some time previous to sounding. The in- 

 strument being carefully introduced, can be moved about in the 

 bladder, and when the stone is touched, a distinct click will be heard, 

 and a sensible impression of impingement will be felt. There are 

 many sources of error in sounding : the instrument may pass over 

 the stone, when lodged in the inferior fundus of the bladder, or the 

 stone may be small and encysted in the mucous coat ; on the other 

 hand we may be deceived by the sound grating against a diseased 



