57 PHYSIOLOGICAL CHEMISTRY 



13 "Salt -free" Diet. In order to be properly nourished we must 

 ingest a certain amount of inorganic matter daily. If we fail to do 

 this our metabolic processes become abnormal and the urine is one 

 index of this abnormality. 1 



Experiment. Ingest an ordinary mixed diet containing an ample salt content 

 for a period of two days. Follow this period by the ingestion of a diet which has 

 had its salt content reduced to a very low value. 2 Sugar and olive oil or non- 

 salted butter may supply the bulk of the calorific part of the diet and dialyzed egg 

 white or casein or commercial protein preparations, e.g., plasmon, gluten or glidine 

 may supply the protein. Ingest such a diet for three days. (This is an "acid- 

 forming" diet, see page 580.) Collect the urine and analyze for sodium chloride, 

 acidity, ammonia and total nitrogen. Compare the data from the normal days 

 with those obtained when the "salt-free" diet was ingested. Test the urine 

 (Chapter XXVI) and blood (Chapter XVI) for acetone. An acidosis follows 

 the ingestion of a salt-free diet for a sufficient length of time. 



Did you feel perfectly normal during the interval you were ingesting the 

 "salt-free" diet? 



14. Salt -rich Diet. On an ordinary mixed diet a normal adult 

 will daily excrete 10-15 grams of chloride, expressed as sodium chloride, 

 in the urine. On a salt-free diet this excretion decreases, whereas if 

 the diet contains an excessive quantity of sodium chloride this excess 

 will be promptly excreted in the urine. Normal feces contain very 

 little sodium chloride even after excessive sodium chloride ingestion 

 (see Experiment 33). 



Experiment. Ingest an ordinary mixed diet for two days. On each of the 

 following two days take a similar diet plus a weighed amount (e.g., 10 grams) of 

 sodium chloride. Collect the urine for the four days in 24-hour samples, pre- 

 serve and analyze for sodium chloride (for methods see Chapter XXVI). What 

 proportion of the added chloride was recovered? 



If it is desired to make the experiment quantitative in character ingest a uni- 

 form diet (see Experiment, page 592) each day instead of the ordinary mixed diet, 

 and examine urine and feces (see Experiment 33) for chloride. 



15. Acidosis. Acidosis may be induced in a normal person by the 

 ingestion of a " salt-free" diet such as described in Experiment 13, 

 above, or by the ingestion of a carbohydrate-free diet. The acidosis 

 appears somewhat earlier under the latter conditions. The non- 

 carbohydrate diet is rather better suited for the demonstration of 

 acidosis because of its greater palatability. When carbohydrates are 

 ingested there is an oxidation of fatty acids to carbon dioxide and 

 water. When no carbohydrates are ingested a portion of the fatty 

 acids are converted into acetone bodies. These are difficult to oxidize 

 and are excreted as such. The ketonuria (excretion of acetone and 



1 Taylor: University of California Publications, Pathology, i. 



2 It is practically impossible to secure an absolutely "salt-free" diet. 



