RESPIRATION AND ACIDOSIS 37 



not occur, at least not to any great extent. Likewise in the absence 

 of carbohydrate in the diet, the oxidation is not complete and acetone 

 bodies are increased in amount in both blood and urine. 



The appearance of the "acetone bodies," i.e., acetone, acetoacetic 

 acid and 0-hydroxybutyric acid in the urine in appreciable quantity was 

 originally taken as the index of an acidosis and the extent of the acidosis 

 was judged by the estimation of the amount of these bodies present 

 in the urine. That this is not a reliable index is shown by the occasional 

 observation of a pronounced acidosis with no appreciable increase in 

 urinary acetone bodies. A high urinary ammonia coefficient (ammonia 

 N: total N) was also early looked upon as an indication of acidosis. 

 However, this factor is not very useful in diagnosis in spite of the fact 

 that the majority of acidosis cases show a high urinary ammonia value. 

 Certain dietetic changes may produce high urinary ammonia, therefore, 

 it is not necessarily indicative of acidosis. It is also true that fatal 

 acidosis has been observed in uremia, and in nutritional disorders 

 of infants, with no pronounced increase in the Ammonia coefficient. 



With the development of blood analysis the content of these acetone 

 bodies in blood plasma was looked to as an aid in the determination of 

 the extent of acidosis. But here again the hope of the clinician failed 

 to materialize. Notwithstanding the fact that acidosis may truthfully 

 be considered as that state of metabolism of which the most constant 

 characteristic is the production of abnormal quantities of acetone 

 bodies, nevertheless, it is the consensus of the best opinion at the pres- 

 ent time that acidosis can be best diagnosed and its course followed 

 not by the determination of acetone bodies in either urine or blood but 

 by the determination of certain other factors which are more or less 

 typical of acidosis. These include the following: 



1. The determination of the "alkali reserve'' of the blood. 



2. The determination of the alkali tolerance of the patient. 



3 . The determination of the carbon dioxide tension of the alveolar air. 



4. The determination of the hydrogen-ion concentration of 



the blood. 



It must be at once apparent that the development of acidosis with 

 its excessive acid formation will tend toward a change in the reaction 

 of the various body fluids, particularly the blood. However, even tn 

 the most severe acidosis there is but slight alteration in the reaction of the 

 blood since the ability of the body to protect itself against the acid 

 production is very remarkable. The normal reaction of the blood 

 is slightly alkaline. If there be but slight deviation from the normal 

 reaction, health rapidly departs and death may ensue. It is therefore 

 of first importance that the reaction of the blood be kept as nearly 



