806 



ORGANIC ANALYSIS. 



crimson liquid is obtained, with nitric a yellow 

 solution attended with effervescence during the 

 action, and with hydrochloric acid a character- 

 istic violet-coloured liquid is procured. 



e. The gelatinous tissues may be shewn to be 

 such by continued boiling in water for twenty- 

 four or forty-eight hours; the liquid, if not too 

 dilute, has then the property of gelatinizing on 

 cooling; with infusion of galls it should pro- 

 duce an abundant flocculent buff-coloured pre- 

 cipitate. 



,/'. Sometimes we meet with concretions formed 

 principally of hairs; their texture and appear- 

 ance generally betray their composition. Be- 

 fore the blowpipe they are dissipated with the 

 well-known smell of burnt feathers. Solution 

 of potash dissolves them slowly, and the liquid 

 then gives the reactions furnished by alkaline 

 solutions of albumen. 



g. Earthy phosphates. Phosphate of lime 

 rarely occurs alone, either as a sediment or cal- 

 culus; though in combination with others it is 

 one of the most usual constituents of morbid 

 concretions. Before the blowpipe, unless mixed 

 with animal matters, it undergoes little change ; 

 usually a transient blackening appears from the 

 charring of a little organic matter always pre- 

 sent ; by continuing the heat it becomes white. 

 Nitric acid dissolves it readily, and phosphoric 

 acid may be shewn by adding acetate of lead 

 as directed when speaking of the detection of 

 phosphoric acid. Ammonia in excess added 

 to the acid solution causes a bulky gelatinous 

 precipitate of bone earth ; on redissolving in 

 acetic acid, and adding oxalate of ammonia, 

 we obtain abundance of oxalate of lime. 



Phosphate of ammonia and magnesia, or, as 

 it is frequently termed, triple phosphate, is a 

 common constituent of calculi and of white 

 sand ; when in the form of a sediment it ge- 

 nerally occurs in hemihedral six-sided prisms ; 

 heated before the blowpipe it emits ammonia, 

 agglutinates, but is almost infusible ; the addi- 

 tion of a fourth or a sixth of its bulk of phos- 

 phate of lime, as a shaving of bone or ivory, 

 causes its immediate fusion to a white enamel- 

 like bead. It is soluble in acids, and ammo- 

 nia causes a crystalline precipitate of unchanged 

 phosphate; phosphoric acid maybe discovered 

 by acetate of lead as before; oxalate of ammo- 

 nia causes no precipitate in the acetic solution 

 unless lime be present. 



Not unfrequently these two kinds are mixed, 

 constituting what has been termed the fusible 

 calculus, from its property of forming the ena- 

 mel-like bead before the blowpipe just men- 

 tioned. Heated with potash it evolves ammo- 

 nia. Phosphoric acid and lime may be shown 

 as before. After the separation of lime by 

 oxalate of ammonia, supersaturation with 

 ammonia throws down the crystalline phos- 

 phate of ammonia and magnesia. 



h. Carbonate of lime. These calculi be- 

 fore the blowpipe are converted into caustic 

 lime, and then give a brown stain to turmeric 

 paper. In dilute nitric or hydrochloric acid 

 they dissolve with effervescence. Lime may 

 be shown in the solution by appropriate tests. 



i. Oxalate of lime is now and then met 

 with, forming a gravel crystallized in pale 

 amber-coloured prisms, but usually in the 

 form of larger concretions, from their tuber- 

 culated exterior termed mulberry calculi ; for 

 the most part they have a dark brown or ma- 

 hogany colour. Heated moderately before the 

 blowpipe they yield a white ash, consisting 

 principally of carbonate of lime, and dissolving 

 with effervescence in acids. If the heat be 

 greater, quicklime alone remains. It stains 

 turmeric paper brown when moistened. Lime 

 may be detected in the ash by the usual re- 

 agents. Oxalate of lime, when powdered, dis- 

 solves in nitric acid readily, more sparingly in 

 hydrochloric acid. Ammonia throws it down 

 unchanged from these solutions, and the preci- 

 pitate is insoluble in acetic acid. 



The whole of the preceding experiments may 

 be made upon portions of matter not exceeding 

 two grains, and most upon a quantity much 

 smaller, especially if our examinations be 

 aided by the microscope. Examinations of 

 these matters are rarely quantitative; the small 

 quantity of material procurable, and an unwill- 

 ingness to sacrifice morbid products of this 

 description for the purposes of analysis, prevent 

 us from possessing information so full and 

 detailed upon the constituents of concretions 

 in general as the numerous collections in exis- 

 tence would have led us to expect. 



Calculi, especially urinary calculi, are far 

 from presenting a uniform and homogeneous 

 structure throughout, being in many if not in 

 most cases composed of lamina: differing mate- 

 rially in composition. It would be of little 

 value to the pathologist to know the compo- 

 nents of all the different layers mingled indis- 

 criminately ; the information he would derive as 

 to the process by which the stone was formed, 

 and of the means by which tendencies to such 

 formations might be counteracted, would be of 

 the most confused and indefinite description, 

 tending rather to mislead than to aid him in 

 forming correct conclusions. Just so it is when 

 chemical analysis is applied to organized tex- 

 tures in general without due regard to the struc- 

 ture and disposition of the proximate elements 

 within them ; and hence the confused medley 

 of substances obtained by subjecting them as a 

 whole to the action of chemical agents. The 

 texture, however, once known, and the action 

 of our reagents upon it being watched under 

 the field of the microscope, we can at pleasure 

 separate the different ingredients, and obtain, 

 with comparatively little difficulty, results 

 which are fixed and producible at will; results 

 which strictly belong to the domain of science, 

 to whose enlargement and successful cultivation 

 they then really contribute. 



When soft tumours or malignant growths are 

 submitted to our examination, one portion must 

 as usual be carefully desiccated, to determine 

 the proportion of moisture ; and another, after 

 being shred finely, macerated for some hours 

 with water at a temperature not exceeding 100 

 F. ; in this way the soluble albumen will be 

 separated from the fibrous and other insoluble 



