" 6. Of mixed or compound calculi. — In one sense of the term, all calculi may be said to be mired or compound, as there are perhaps none absolutely pure, i.e., formed of a single in gredient. But in the sense in which the term is here applied, namely, as expressive of cal culi composed of different ingredients mixed together in large or nearly equal proportions, compound calculi may be said to be rare. The most usual mixtures consist of the lithate of ammonia and of lime; of the oxalate, car bonate, and phosphate of lime ; of the lithate of ammonia, and the mixed phosphates, &c. ; and such mixtures are usually confined to small calculi or calculous nuclei. Calculi composed of pure lithic acid, or of any other pure ingredient, with the phosphates or other compounds, do not appear to exist ; at least I have met with no such mixtures.
" Lastly, it remains to make a few remarks on the order of calculous deposits ; an inquiry that throws considerable light on the laws of their formation and general pathology.
" On reference to the table it will be found, that in the different alternating calculi, the ratio in which the oxalate of lime succeeds to lithic acid, is as 1 : 156+ ; off the contrary, that the ratio in which lithic acid succeeds to oxalic acid, is as 1 : Hence the alter nation of the two ingredients may be con sidered as nearly equal. It will be found, however, that the oxalate of lime succeeds to the lithate of ammonia, &c., more frequently than to lithic acid ; thus the ratio in which the oxalate of lime succeeds to the lithate of ammonia was 1 94—. On the contrary, the ratio in which the lithate of ammonia succeeds to the oxalate of lime, is only as 1 : 38 ; a very striking distinction. The ratio in which the phosphates succeed to lithic acid, is as 1:96— ; in which the phosphates succeed to the lithate of ammonia, is as 1 : 121— ; and in which the phosphates succeed to the oxa late of lime, is as 1 71+. On the contrary, three instances only occur in which the lithic acid or lithate of ammonia succeeds to a phosphate ; and the proportion in which the oxalate of lime succeeds to the phosphates is as 1 : 2531 only. The general proportion in which the phosphates succeed to the other ingredients in all the collections, is as 1 : Hence the generality of the im portant law alluded to in various parts of this volume, that in urinary calculi a decided depo sition of the mixed phosphates is not followed by other depositions." The following table, constructed by Dr.
Prout, illustrating the frequency of calculous affections at different ages, and in the different sexes, is from a paper published by Mr. Smith in the eleventh volume of the Med. Chirurg. Transactions, and from " A Treatise on the Formation, Constituents, and Extraction of Urinary Calculi. By John Green Crosse, Esq., Surgeon to the Norfolk and Norwich Hospital. London, 1835." Urine in disease may not only show a tendency to deposit matters of an insoluble character in the form of urinary deposits or calculi, but it may also contain in solution an excess or deficiency of any one or more of its normal constituents. There may likewise be present in solution matters altogether foreign to the healthy constitution of the fluid. The urine in disease may then, so far as its dis solved matters are concerned, be considered in two points of view, viz. 1. Excess or defi ciency of Armal constituents ; 2. Presence of matters not existing in healthy urine.
I shall proceed to notice the state of the urine in those forms of disease in which it has received attention, and shall quote from the work of Franz Simon, who not only laboured long and well on the subject, but collected much valuable information relating to it. Before doing this, however, I must notice the ingenious attempt made by Bec querel to classify all diseased conditions of urine under four heads, viz. 1. Febrile. urine ; 2. Anmmic urine ; 3. Alkaline urine ; 4. Urine but slightly varying from the conditions of health.
I will shortly notice the principal cha racters of these four varieties.
1. Febrile urine.—a. Febrile urine, strictly speaking.—The proportion of water passed in the twenty-four hours less than in health. Solid matters slightly diminished in propor tion. Urea and inorganic salts deficient. Uric acid increased in proportion. Colour high. Specific gravity above the normal standard. Often turbid from lithates. Some times contain albumen.
This latter statement of Becquerel's must be received with some reservation. Thus I have several times known a deposit produced in urine in adynamic forms of fever on the addition of nitric acid, which proved, on ex amination, to be lithic acid and not albumen.
The following are the conditions in which, according to Becquerel, the urine assumes the febrile character ; viz., in chronic and acute inflammations; in diseases of the liver, heart, and lungs; in haemorrhages, and in organic degenerations of organs resulting from fever or long functional derangement.