URINARY CALCULI. 



capable of being diflblved m cold water ; that this folution 

 poffefled acid properties, and, in particular, that of red- 

 dening litmus ; that it was afted upon in a peculiar manner, 

 •whenboiled in nitric acid ; and, laftly, that human urine 

 always contained this fubftance in greater or lefs quantity, 

 and often let it feparate in the form of a brick-coloured fedi- 

 ment, by the mere effeft of cooling. 



The difcovcry made by Scheele was confirmed by Berg- 

 mann and Morveau, and the inveftigation of the fubjeft was 

 afterwards profecuted by others with redoubled ardour. 

 As profefTor Murray obfer\es, experiments continued to be 

 repeated and diverfified on thefe concretions, and on their 

 folvents. At length, it was fully afcertained, that there ex- 

 ifted others, befides thofe compofed of uric acid ; and, lat- 

 terly, our knowledge of them has been much extended by 

 the refearches of Pearfon, Wollafton, Fourcroy, and Vau- 

 quclin. Several important fafts have alfo been eftabliflied 

 by the talents and iiiduftry of fome other diftinguiflied men ; 

 •viz. Dr. Henry of Manchefter, profefTor Brande of the 

 Royal Inftitution of London, and Dr. Marcet of Guy's 

 hofpital. 



The credit which is due to Dr. Wollafton, for his valu- 

 able and original difcoveries refpefting urinary calculi, is 

 very confiderable ; a truth which we have particular pleafure 

 in recording here, fince his merits have not been fairly ap- 

 preciated by the French chemifts. Indeed, as Dr. Marcet 

 obferves, it is the more defirable that his claims fhould be 

 placed in the cleareft point of view, as the late celebrated 

 M. Fourcroy, both in his " Syftcme des ConnoifTances 

 Chimiques," and in his various papers on this particular 

 fubjeft, has, in a moft unaccountable manner, overlooked 

 Dr. Wolkilon's labours ; and in defcribing refults, exaftly 

 fimilar to thofe previoufly obtained and publiflied by the 

 Englifh chcmift, has claimed them as his own difcoveries. 

 Yet Dr. WoUafton's paper was printed in our Philofophical 

 Tranfaftions two years before Fourcroy publifhed his 

 memoir in the " Annales de Chimie," and three years be- 

 fore he gave to the world his " Syfteme des ConnoifTances 

 Chimiques ;" and he difcufTed in thefe works a paper of 

 Dr. Pearfon on the lithic acid, publifhed in a volume of the 

 Philofophical Tranfaftions for 1798, fubfequent to that 

 which contained the account of Dr. WoUafton's difcoveries. 

 EfTay on Calculous Diforders, p. 60 ; alfo Murray's Syft. 

 of Chem. vol. iv. p. 636. edit, of 1809. 



From what has been ftated, it appears, then, that Scheele 

 firft difcovered the nature of thofe urinary calculi which 

 confift of lithic acid ; but that Dr. W'oUafton lirft afcer- 

 tained the nature of feveral other kinds, fome of which have 

 alfo been defcribed at a later period by Fourcroy and Vau- 

 quelin. On the wliole, there are live fpecies of concretions, 

 whofe chemical properties were firft pointed out by Dr. 

 Wollafton, and no Icfs than four belong to the urinary or- 

 gans. Thefe are, ill, Gouty concretions; 2dly, The 

 fufiblc calculus ; 3dly, The mulberry calculus ; 4tlily, The 

 calculus of the proftate gland ; Jthly, The cyltic oxyd, 

 which laft was difcovered in 18 10. 



Dr. Marcet, in his late ingenious cffay, arranges urinary 

 calculi under the following heads : 



1. The lithic calculus. 



2. The bone-earth calculus, principally confifting of 

 phofphate of lime. 



3. The ammoniaco-magnefian phofphate, or calculus in 

 which this triple fait obvioufly prevails. 



4. The fufible calculus, confifting of a mixture of the two 

 former. 



5. The mulberry calculus, or that compofed of oxalate 

 of lime. 



Vol. XXXVII. 



6. The cyftic calculus, confifting of tlie fubftance called 

 by Dr. Wollafton cyftic oxyd. 



7. The alternating calculus, or concretion compofed of 

 two or more different fpecies, arranged in alternate layers. 



8. The compound calculus, the ingredients of which are 

 fo intimately mixed, as not to be feparable without chemical 

 analyfis. 



9. Calculus of the proftate gland. 



Dr. Marcet likewifc defcribes two other fpecimens, which 

 are not referrible to any of the foregoing fpecies. 



1. Lithic or Uric Acid Calculus. — The lithic acid forms a 

 hard, inodorous concretion, of a yellowifh or brown colour, 

 fimilar to that of wood, of various (hades. According to 

 profefTor Murray, calculi of this kind are in fine, clofe layers, 

 fibrous, or radiated, and generally fmooth on their furface, 

 though fometimes a little rough. They are rather brittle, 

 and have a fpecific gravity, varying from 1.276 to 1.786, 

 but ufually above 1.500. One part of lithic acid is faid to 

 difTolve in 1720 parts of cold water, and 1150 parts of 

 boiling water (Marcet, p. 65.); and tliis folution turns 

 vegetable blues to a red colour. When it has been diffolved 

 in boiling water, fmall yellowifli cryftals are depofited as the 

 fluid becomes cold. Lithic acid calculi blacken, but are 

 not melted by the blow-pipe, emitting a peculiar animal 

 fmell, and gradually evaporating, until a fmall quantity of 

 white afh remains, which is alkaUne. By diftillation, they 

 yield ammonia and prufTic acid. They are foluble, in the 

 cold, in a folution of pure potafTa, or foda ; and from the 

 folution, a precipitate of a fine white powder is thrown down 

 by the acids. Lime-water like wife difTolves them, but more 

 fparingly. In folutions of the alkaline carbonates, they re- 

 main, according to Scheele, unchunged : according to the 

 experiments of Dr. Egan, however, they are difTolved even 

 by a weak folution, and alfo when the acid is fuperfaturated 

 by carbonic acid. (Tranf. of Irifli Acad. 1805.) They 

 are not much afted upon by ammonia. They are not fo- 

 luble either in the muriatic or fulphuric acid ; though they 

 are fo in the nitric, when afTifted by heat ; and the refidue 

 of this folution, when evaporated to drynefs, affumes a re- 

 markably bright pink colour, which diiappears on adding 

 cither an acid or an alkali. In many of thefe calculi, the 

 lithic acid is nearly pure ; in others, there is an intermixture 

 of other ingredients, particularly of phofphate of lime, and 

 phofphate of ammonia and magnefia ; and, in almoft all of 

 them, there is a porticfti of animal matter, which occafions 

 the fmell, when they are burnt, and tlie lofs in their ana- 

 lyfis. See Murray's Chemiflry, vol. iv. p. 640 ; and Mar- 

 cet's EfTay on the Chem. and Med. Hift. of Calculous 

 Diforders. 



2. Bone-earth, or Phofphate of Lime Calculus. — The ex- 

 iftence of phofphate of lime in urinary calculi had been men- 

 tioned by Bergmann and others, when Dr. Wollafton firft 

 afcertained that fome calculi are entirely compofed of it, 

 forming a diftinft fpecies of thefe concretions. From the 

 obfervations of the laft mentioned eminent chcmift, it ap- 

 pears that this fubftance fometimes compofes the entire 

 calculus ; though, in more common inftances, it is mixed 

 with other ingredients, particularly with uric acid, and with 

 phofphate of magnefia and ammonia. In the firft cafe, th« 

 calculus is defcribed as being of a pale brown colour, and fo 

 fmooth as to appear polifhed. When fawn through, it is 

 found very regularly laminated, and the laminx, in jjeneral, 

 adhere fo flightly to each other, as to feparate with eafc 

 into concentric crufts. It difi'olves entirely, though (lowly, 

 in muriatic or nitric acid. Expofed to the flame of the 

 blow-pipe, it is at firft Higlitly charred, but foon becomes 

 perfectly white, retaining itb form, until urged with the ut- 



3 X moft 



