SBCT. 190] THE URINE. 4T 9 



of the urine undergoes decomposition into lactic and acetic acids ; and by 

 this means the uric acid is freed from its combinations, and is precipitated 

 in the fi irm of rhombic or prismatic crystals, coloured yellow or reddish by 

 the colouring matter of the urine. The acid disappears earlier or later, the 

 urine becomes ammoniacal and alkaline by the decomposition of the urea, 

 and. perhaps, also of the colouring matter, and large colourless pyramidal 

 prisms or stellately disposed needles of ammoniaco-magnesian phosphate, 

 soluble in acetic acid (triple-phosphate), make their appearance ; these, 

 mingled with numerous infusoria (vibrions and monads), form a superficial 

 pellicle and a white sediment, in which the crystals of triple-phosphate are 

 mixed with granules of urate of ammonia, and, perhaps, also of carbonate of 

 lime. Under exceptional circumstances, which we do not yet understand, 

 there appear in the urine the six-sided prisms of cystine, but a more frequent 

 deposit is composed of oxalate of lime, in the form of octohedra insoluble in 

 acetic acid : these occur especially after the use of aerated drinks, and also in 

 pregnant women. The uric acid becomes increased, after the use of highly 

 azotised food, after disturbance of the digestion, by want of exercise, in 

 fevers, etc., and then there forms, on the cooling of the urine, a yellowish 

 sediment, more or less abundant, of urate of soda, in the form of granules, 

 isolated or collected in heaps, and dissolving when the urine is heated. If 

 now the acid fermentation begin, the most abundant sediments of coloured 

 crystals of uric acid (brick-red sediments) are often thrown down. In affec- 

 tions of the bladder, the urine often becomes quickly alkaline, and then the 

 above-mentioned crystals of triple-phosphate immediately present them- 

 selves. The latter are also very frequently observed in pregnant females, 

 and in the form of the above-mentioned pellicle, were at first held to be a 

 peculiar substance (Kicsthvin). 



The occurrence of albumen, fibrine, and fat, in the interior of the urinary 

 tubules, can, in my opinion, be easily explained, on the assumption that in these 

 cases a disturbance of the circulation takes place with an increased transu- 

 dation of the constituents of the blood into the Malpighian corpuscles and the 

 urinary tubules ; and that, in consequence of this exudation, the epithelium of 

 these parts becomes detached. This would account for the well-known fact, that, 

 in these cases, epithelium appears in the urine in large quantities ; and we may 

 be sure, that after such separation of the epithelial cells, there would be no 

 further hindrance to the passage of the albumen and fibrine. It is, indeed, 

 conceivable, that the fibrine should escape by penetrating the epithelium, as 

 we know may occur in the instance of the respiratory mucous membrane ; 

 but I do not believe that an amount of pressure sufficient to produce a 

 transudation of fibrine, would leave the delicate epithelium uninjured. 

 When once the epithelium is wanting, it is very questionable whether it is 

 quickly reproduced ; and it appears to me, that the frequent occurrence of 

 Mil dl quantities of albumen in the urine may often be dependent upon 

 nothing else than a local absence of the epithelium. 



Investigation of the Kidneys. — The urinary tubules can be readily isolated 

 by teasing them out, and the epithelium, membrana propria, and cavity be- 

 come distinctly recognisable when moistened with the serum of blood or a 

 solution of albumen. Along with entire tubules, there are found, in every 

 preparation, numerous epithelial cells, isolated and in heaps, or even forming 

 continuous long tubes : these latter are met with chiefly in the pyramids, and 



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