ACID FERMENTATION OF URINE. 



407 



{Kunkel, v. Voit 177, 6). Hyposulphurous add, as an alkaline salt, is an abnormal con- 

 stituent in typhus ; and so is sulphuretted hydrogen, which is recognised by the blackening of 

 a piece of paper moistened with lead acetate and ammonia, held over the urine. 



4. Excessively minute traces of silicic acid and nitric acid derived from drink- 

 ing water have been found in urine. Organic acids, e.g., citric and tartaric, when 

 taken internally, increase the amount of carbonates in the urine. The urine may 

 effervesce on the addition of an acid. 



The sodium in the urine is chiefly combined with chlorine, but a small part of 

 it is united with phosphoric and uric acids ; potassium (which is about J- of the 

 sodium) is chiefly combined with chlorine. In fevers, more potash is excreted than 

 soda, and during convalescence, the reverse is the case ; calcium and magnesium 

 exist in normal acid urine as chlorides or acid phosphates. If the urine is neutral, 

 neutral calcium phosphate and magnesium phosphate are precipitated. Ebstein 

 found the latter in alkaline urine, as large clear four-sided prisms, in diseases of the 

 stomach. If the urine is alkaline, calcium carbonate (fig. 281) and tribasic calcic 

 phosphate are deposited as such, while the magnesium is precipitated in the form 

 of ammonio-magnesium phosphate, or triple phosphate. The calcium is derived 

 from the food, and depends upon the amount of lime salts absorbed from the 

 intestine. Free ammonia is said to occur (0*72 gramme, or 7 grains daily) in per- 

 fectly fresh urine (Neubauer, Brilche), and the amount is greater with an animal 

 than with a vegetable diet (Coranda). The amount of fixed ammonia is increased 

 by the administration of mineral acids (Walter, Schmiedeberg, Gdthgens). Iron (1 

 to 1 1 milligrammes per litre) is never absent. There is a trace of hydric peroxide 

 (Schonbein), which is detected by its decolorising indigo-solution on the addition of 

 iron sulphate. 



Gases. 24 "4 c.c. of gas was obtained from one litre of urine 100 volumes of the gases 

 pumped out consisted of 65*40 vol. C0 2 , 2*74 0, 13 "86 N. After severe, muscular action, the 

 amount of C0 2 may be doubled ; digestion also increases it, copious drinking diminishes it. 



263. FERMENTATIONS OF URINE. Acid Fermentation. When per- 

 fectly fresh urine is set aside, it gradually becomes more acid from day to day. 

 This is called the " acid ferment- 

 ation." It seems to be due to 

 the development of special fungi 

 (fig. 260, a), and the process is 

 accompanied by the deposition of 

 uric acid (c), acid sodium urate, in 

 amorphous grains (6), and calcium 

 oxalate (d). According to Scherer, 

 the fungus and the mucus from 

 the bladder decompose part of the 

 urinary pigment into lactic and 

 acetic acids. The latter sets free 

 acid from neutral sodium 



d 



uric 



urate, so that free uric acid and 

 sodium urate must be formed. 

 Butyric and formic acids have been 

 found as abnormal decomposition- 

 products of other urinary constitu- Deposit in 



^0V 



3 tZ f \<P*r ^ 



Fig. 260 

 acid fermentation 



b, amorphous sodium urate 

 oxalate. 



of urine, a, fungus ; 

 c, uric acid ; d, calcium 



ents. When the acid fermentation 



begins, the urine absorbs oxygen 



(Pastew). According to Briicke, it is the lactic acid, formed from the minute 



traces of sugar present in urine, which causes the acidity. According to Rohmann, 



who recognises the acid fermentation as an exceptional phenomenon, the acids are 



formed from the decomposition of sugar, and from alcohol which may be present 



