ACIDITY OF THE URINE. 641 



The composition of the food is not the only influence which affects 

 the degree of acidity of human urine. For example, after taking food 

 at the beginning of digestion, when a larger amount of gastric juice con- 

 taining hydrochloric acid is secreted, the urine may be neutral or even 

 alkaline. 1 As to the time of the appearance of the maximum and 

 minimum of acidity, the various investigators do not agree, which may* 

 in part be explained by the varying individuality and conditions of 

 life of the persons investigated. It has not infrequently been observed 

 that perfectly healthy persons in the morning void a neutral or alkaline 

 urine which is cloudy from earthy phosphates. The effect of muscular 

 activity on the acidity of urine has not been positively determined. 

 According to HOFFMANN, RINGSTEDT, ODDI, and TARULLI and VOZARIK 

 muscular work raises the degree of acidity, but ADUCCO 2 claims that it 

 decreases it. Abundant perspiration reduces the acidity (HOFFMANN) . 



In man and especially in carnivora it seems that the degree of acidity 

 of the urine cannot be increased above a certain point, even though 

 mineral acids or organic acids which are burnt up with difficulty are 

 ingested in large quantities. When the supply of carbonates of the 

 fixed alkalies stored up in the organism for this purpose is not sufficient 

 to combine with the excess of acid, then ammonia is split off from the 

 proteins or their decomposition products, and this excess of acid combines 

 therewith, forming ammonium salts, which pass into the urine. In her- 

 bivora such a combination of the excess of acid with ammonia seems 

 not to take place, or not to the same extent, and therefore herbivoia 

 soon die when acids are given. This is true at least for rabbits, while 

 according to BAER 3 this power of increasing the elimination of ammonia 

 exists also in the goat, monkey, and pig, hence no definite difference in 

 this regard exists between herbivora and carnivora. The differences 

 which have been observed are, according to EPPINGER, not of a special 

 kind, and they may be caused, he says, from a different amount of 

 protein in the food which yields ammonia. One can by food rich 

 in protein make herbivora (also rabbits) resistant toward the intro- 

 duction of acid, while dogs with food poor in protein behave like 

 rabbits. The question as to the action of acids upon the elimination 

 of fixed alkalies by the urine and the removal of these from the tissues 

 seems to be rather complicated as, according to STAAL, in rabbits the 

 quantity of sodium in the subcutaneous connective tissue is not diminished 

 after the continuous introduction of acid for several days, but is rather 



1 Contradictory statements are found in Linossier, Maly's Jahresber., 27. 



2 Hoffmann, see Maly's Jasresber., 14; Ringstedt, ibid., 20; Oddi and Tarulli, 

 ibid., 24; Aducco, ibid., 17; Vozarik, Pfliiger's Arch., 111. 



3 See Winterberg, Zeitschr. f. physiol. Chem., 25, and J. Baer, Arch. f. exp. Path. u. 

 Pharm., 54. 



