174 GRAVEL GRAVEL, substances consolidated and pre- cipitated from the urine within the body, in certain diseased conditions of the system, dif- fering from calculi by their small size, and generally voided without surgical interference. (See CALCULI.) The appearance of gravel is important as evidence of a disposition to cal- culous deposits, and as indicating the proper treatment. When the disposition exists, any- thing which obstructs the passage of urine fa- vors the precipitation of gravel. There are three kinds of gravel, as there are three princi- pal forms of calculi, viz. : the lithic, the ox- alic, and the phosphatic. Lithic or uric acid, a highly nitrogenous compound, exists normally in the urine in combination with soda ; if the urine be abormally acid, the lithic acid will be precipitated in a crystalline form, constituting the lithic or red gravel ; lithic acid when pure is white, but in human urine it assumes the tint of its coloring matter, which causes it to look like Cayenne pepper. The urine con- taining this gravel is generally acid, high-col- ored, scanty, but clear ; in what is called a " fit of the gravel," this acid is precipitated in large quantity, accompanied by fever, pains shooting from the loins to the bladder, frequent and scalding micturition, &c. The causes which predispose to the excessive formation of lithic acid have been detailed in the article GOUT, with which disease gravel is intimately con- nected ; it will be sufficient to say here that the use of highly nitrogenous food and stimulating drinks, and sedentary or slothful habits, are very likely to induce both gout and lithic acid gravel. Though not unfrequently occurring in children, gravel is most common between the ages of 40 and 65 ; it is comparatively rare in warm climates, or in persons living chiefly on vegetable food. On the principles of Lie- big, the great indication for the treatment of the red gravel is to promote the action of oxy- gen on lithic acid so as to cause its conversion into urea and carbonic acid, and its consequent escape from the system through the urine and the perspiration ; in other words, to take in an increased supply of oxygen by exercise in the open air, by preparations of iron, and by the nitro-muriatic acid ; to moderate the quan- tity of highly nitrogenous food, avoiding that containing much starch and sugar, as well as malt and fermented liquors; to secure a healthy action of the skin by suitable clothing and at- tention to cleanliness ; to remove all intestinal obstructions, and to neutralize acidity, if neces- sary, by the administration of alkalies. The lithic acid gravel may be regarded as the sign of an inflammatory or congestive habit, but the next form, or the oxalic acid gravel, belongs to an irritable or nervous constitution, and is usually accompanied by a dry skin, dyspepsia, boils, carbuncles in advanced life, and nervous exhaustion or despondency ; the urine is trans- parent, pale greenish yellow, of moderate speci- fic gravity, and free from sediments, but con- taining minute crystals of oxalate of lime. The GRAVELOTTE causes of this diathesis are such as produce dyspepsia, nervous debility, and hypochondriac diseases : residence in malarious districts, and unwholesome vegetable food. The treatment is very similar to that for lithic acid gravel, it being remembered that in this case the sys- tem craves less oxygen ; distilled water is ad- vised in order that lime may not in this way be introduced into the system and endanger the formation of mulberry calculi; alkalies, with ammonia, tonics, and the mineral acids, are required according to circumstances. Oxa- late of lime deposits, however, are usually much less abundant and less irritating than those of uric acid, and, as a general rule, are less important indications of an unhealthy state of the system. The white gravel may be either the ammoniaco-magnesian phosphate or the phosphate of lime, or the mixture of the two. The earthy phosphates are naturally held in solution by the acid reaction of the urine ; and when this is neutralized or replaced by an alkaline reaction, these phosphates are precipitated in the form of a white amorphous powder. If the urine become ammoniacal, a new compound is formed, namely, the triple phosphate of magnesia and ammonia. This substance has the form of three-sided pris- matic crystals, sometimes large enough to be distinguished by the naked eye. The phos- phatic diathesis is generally seen in pale and weak persons, complaining of nervous exhaus- tion, as Dr. Prout maintains, on account of the great consumption of phosphorus in ner- vous diseases ; it may be produced by exces- sive fatigue of body or mind, intense study, unwholesome food, weakening medicines, and chronic urinary affections. The treatment should consist of tonics. GRAVELINES (Flem. G-ravelinglie ; Ger. Gra- velingeri), a fortified seaport town of France, in the department of Le Nord, near the mouth of the Aa, 10 m. W. S. W. of Dunkirk ; pop. in 1866, 6,510. It contains a handsome market place, a church built in the 16th century, and a modern town hall, and has an extensive coast- ing trade and active fisheries. Cheese, butter, and eggs are exported ; sail cloth and linens are manufactured, and there is some ship build- ing. The town was founded in 1160 by Count Thierry of Alsace and Flanders. A famous victory was achieved here by the Spaniards under Egmont over the French under the marshal de Thermes, July 13, 155,8. It was annexed to France by the treaty of the Pyre- nees (1659). Louis XIV. had new fortifica- tions constructed, designed by Vauban. GRAVELOTTE, a village of Germany, in Al- sace-Lorraine, on the Moselle, 8 m. W. of Metz ; pop. 700. Here on Aug. 18, 1870, the first and second German armies, commanded by Gen. Steinmetz and Prince Frederick Charles under King William in person, obtained a great vic- tory over the French under Marshal Bazaine. The battle of Gravelotte decided the fate of Metz. It was probably the bloodiest and the
