THE URINARY ORGANS. 211 



continuous strings or tubes. Sedimentary deposits of the salts 

 of the urine are readily formed as the products of decomposition. 

 All normal urine without sediment, at a mean temperature, 

 undergoes an acid fermentation, under the influence of the 

 mucus contained in it ; and whilst fermentation and filamentary 

 fungi are developed, forms, from the decomposition of the 

 urinary colouring matter, lactic or acetic acid, in consequence 

 of which uric acid is set free from its compounds and deposited, 

 in the form of rhombic or prismatic crystals, coloured yellow or 

 reddish by the colouring matter of the urine. Sooner or later 

 the acid disappears, and from the decomposition of the urea, 

 perhaps also of the colouring matter, the urine becomes ammo- 

 niacal and alkaline, with large colourless pyramidal prisms, or 

 needles grouped in a stellate fashion and soluble in acetic acid, 

 of the triple phosphate of magnesia and ammonia, which, in- 

 termixed with numerous infusoria (vibriones and monades), 

 form a superficial pellicle, and with granules of urate of 

 ammonia, and also, it may be, of carbonate of lime, a white 

 sediment. Under conditions not as yet known, and rarely, 

 hexahedral prisms of cystin appear in the urine; more frequently, 

 after the use of drinks containing carbonic acid, and also in 

 pregnant women, we find the octohedrons of oxalate of lime 

 insoluble in acetic acid. If the quantity of uric acid be aug- 

 mented, as after the inordinate use of nitrogenous food with 

 deficient exercise, in impaired digestion, fevers, &c. a more or 

 less abundant yellowish precipitate of urate of soda, in the form 

 of isolated or aggregated granules, is formed as soon as the 

 urine cools, and becomes re-dissolved when it is again warmed. 

 If, under these circumstances, the acid fermentation is set up, 

 very considerable sediments of coloured crystals of uric acid 

 (brick-dust sediment) are often thrown down. In injuries of the 

 bladder, the urine frequently becomes alkalescent with great 

 rapidity, when the above-mentioned crystals of triple phosphate 

 at once make their appearance ; they are also very frequent in 

 pregnancy; and when assuming the pellicular form above 

 described, were at one time regarded as a peculiar substance 

 (Kiestein). 



The occurrence of albumen, fibrin, and fat, within the 

 tubuli uriniferi, is, in my opinion, easily explained, upon the 

 supposition that in such cases, the circulation is obstructed, and 



