558 ABNORMALITIES IN METABOLISM 



Increase of Ch. 



Decrease of base Diarrhea and hemorrhage, respectively (may explain 



acidosis in cholera and in certain forms of shock).*' 



Decrease in Ch. 

 Addition or accumulation Ammonia (faulty metabolism of urea). 



of base Intestinal putrefaction (infantile conditions). 



Administration of alkalies (experimental). 

 Removal of adds Excretion of CO2 (excessive pulmonary ventilation, as 



in faulty ether administration). 

 Excretion of acid urine. 



Practically, acidosis results either from defective oxidation of 

 organic acids formed in metabolism or from defective elimination of 

 mineral acids (acid phosphate) because of impaired renal function. 

 The chief example of the former is the acidosis of diabetes, of the 

 latter the acidosis of nephritis, and mixed forms may occur. 



The degree of acidosis may be estimated in several ways; as 

 follows :^^ 



1. By determining the CO2 content of the blood, which must decrease as other 

 acids increase, or as the bases decrease. 



2. Direct estimation of the H-ion concentration of the blood. 



3. By determining the amount of acid or alkali necessary to change the reaction 

 of the blood to different indicators. 



4. Determination of the CO2 tension of the alveolar air, this varying directly 

 with the CO2 tension of the arterial blood. 



5. The "alkali tolerance test" of Sellards, which consists in ascertaining the 

 amount of sodium bicarbonate that must be taken by mouth in order to produce 

 an alkaline urine. 



6. Estimation of the amount of organic acids, H-ion concentration, and 

 ammonia content of the urine; a method which is fundamentallj^ defective since 

 it indicates merely the acids and bases that have been removed from the body 

 and not those that remain to modify its reactivity. 



7. Determination of the capacity of the blood serum to bind CO2. Normal 

 serum binds about 55 to 75 per cent, of its volume of CO2, whereas in acidosis it 

 may bind but 20 per cent. (Van Slyke) 



Diabetic Coma^* 



In man, poisoning with inorganic acids, as in the experiments cited 

 above, is a rare occurrence, but not infrequently acid intoxication re- 

 sults from the presence of undue quantities of organic acids produced 

 in metabolism. The most striking example of this is the coma of 

 diabetes, in which the asphyxia without cyanosis, dependent upon fail- 

 ure of the blood to carry CO2, is sometimes strikingly similar to that 

 observed in experimental animals poisoned with acids. In diabetic 

 coma the acid intoxication is due chiefly to the accumulation in the 

 blood or tissues of large quantities of ^-oxybutyric acid. Associated 

 with it, in smaller quantities, are usually found diacetic (accioocctic) 

 acid and acetone, which are chemically so closely related that it has been 



^^ To thi.s may be added loss of base from biliary or pancreatic fistulse. 



