1sl VKTOK C. MYKKS 



lion ,,f IIIIIKIIV acidity i. the pi-upm-lion between the ncjd -odium 

 phosphate ( IL.\';il'< >, ) ;iml (In- basic sodium phosphate ( 1 1 N'^-PO., ) , ||,e 

 former raising tho acidity ;in<l the littler lowering it. Tin- principiil iicid 

 supply is found in the metabolism of protein, during which sulphuric ;I.-K| 

 JH formed froin tli<- oxidation of (lie Hidplinr of iln- protein, while plm 

 phorir neid is set free. The organic ncids, uric, hippuric, oxalic, ;md 

 certain of the lower fatty acids also contribute to the acidity. The |, : i ic 

 rudicalH concerned are sodium, |M>lassium, ammonium, calcium and ma- 

 neHinm. The excretory function of the kidney normally prevents any 

 undue accumulation of either acids or liases in the hod\ , thereby ni:iin 

 i. iinnr- a remarkable constancy in (he reaction of the body fluids. 



I'rine is most commonly acid to litmus. Tho reaction and decree of 

 acidity may, however, experience marked change unde.r both physiolo:ir;il 

 and |iatholo^ical conditions. The diet is ono of the inosl importaiil factors 

 involved. In general, the metabolism of animal foods, except mill<, results 

 in an ineroaHcd acidity, while vegetable foods, except the cereal [{rain . 

 tend to diminish the acidity or even yield alkaline mine The re;i on 

 for tliiw general diU'erenc*^ hctweeii animal and ve^etahle food materials is 

 due, an jxiirited out by Slienman and (JiMtler, to their execHH of acid- or base- 

 forming elementH. ThcHe considerations probably account for the fact 

 that tho urine of dogs is normally acid, while that of rabbits is habitually 

 alkaline. 



The pathological formation of acids (as in diabetes) is coiinleriiele.l 

 in a measure by the neutralising action of the bases, sodium, poln mm 

 calcium and inagtiesium. When the acidity .is so great that an adequate 

 .supply of those elements can no longer be economically furnished by the 

 Ixidy, ammonia is called upon to meet this need. This accounts for the 

 increased elimination of ammonia in diabetic kotosis. Tho proximity to a 

 meal may alTwt the reaction of the urine. For example, the secretion of 

 hydrochloric acid in the stomach during the process of digestion may so 

 reduce tho store of acids in the body that for a time after a meal the 

 urine may be neutral or even alkaline, giving rise to tho so-called "alka- 

 line tide." 



Quantitative expression may he given to the acidity of the urine by 

 determining the number of cubic centimeters of tenth normal sodium 

 hydroxid required to neutrali/e the total volume of urine eliminated in 

 24 hr. This represents tho liiralahlc acidity, and may range from 2<><> 

 to f0(), with an average of about MM). 



The tUratahli' an<lHi/ should be distinguished from the Inn- n<-/</i/i/. 

 tho latter depending upon the concentration of ioni/.ed hydrogen (IP). 

 From this point of view, a solution is acid, neutral or alkaline, depending 

 upon tho relative concentrations of hydrogen ions (IT) and of hydroxyl 

 ions (Oil"). An acid solution therefore contains a greater concentration 

 of (IP) than of (Oil"). For convenience in recording the hydrogen ion 





