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VICTOE C. MYEKS 



serum. Normally the chlorid content of whole blood as NaCl amounts in 

 round numbers to 0.45 to 0.50 per cent, while for the plasma the figures 

 are about 0.12 per cent higher, i.e., 0.57 to 0.62 per cent. Since the 

 plasma, rather than the whole blood, bathes the tissues of the body, it 

 would seem more logical to study the chlorid content of the plasma. Un- 

 fortunately, unless the plasma is quickly separated from the corpuscles 

 there appears to be a gradual change (increase) in its chlorid content, 

 owing to a passage of carbon dioxid from the plasma into the corpuscles 

 (or its escape into the air) and of chlorids from the corpuscles to the 

 plasma. This being the case, results obtained on whole blood would ap- 

 pear to be more trustworthy than those obtained on plasma. 



As far back as 1850 Carl Schmidt, in his classic studies on the blood 

 with special reference to cholera, gave figures for the chlorid content of 

 whole blood and plasma. Low figures were obtained in many cases of 

 cholera, apparently as the result of the concentration of the blood, while 

 in a case of "chronic edema with albuminuria" a definite increase was 

 observed. McLean has devoted considerable attention to the subject of 

 the chlorids of the blood working along lines similar to those of Ambard. 

 In a fairly large series of normal individuals he found the plasma chlorid 

 to vary from 0.57 to 0.62 per cent with a very constant chlorid threshold 

 of about 0.562 per cent. The threshold was calculated from the formula 

 of Ambard and Weill and confirms their observation on this point. Mc- 

 Lean considered the question of the plasma chlorids in a number of patho- 

 logical conditions, the lowest observation being 0.50 per cent in a diabetic 

 and the highest 0.84 per cent in a cardionephritic shortly before death. 

 In general, relatively increased concentrations of chlorids were found in 

 the plasma in certain forms of cardiac and renal disease, while decreased 

 concentrations were noted in certain diabetic and fever patients, also 

 after the action of digitalis, the decreased concentrations apparently re- 

 sulting from a temporary or permanent lowering of the chlorid threshold. 

 Failure to excrete chlorids in pneumonia was found to be associated with 

 a lowered concentration of chlorids in the plasma, excretion reappearing 

 with a rise in the plasma chlorid. Edema was usually found to be accom- 

 panied by a relatively increased concentration of chlorids in the plasma, 

 which ordinarily returned to the normal state with the disappearance of 

 the edema. 



In general it may be stated that high blood chlorids have been found in 

 nephritis, certain cardiac conditions, anemia and some cases of malig- 

 nancy (possibly due to an accompanying renal involvement), while low 

 values have been observed notably in fevers, diabetes, pneumonia and 

 Asiatic cholera. The chlorid retention in most cases of nephritis appar- 

 ently results from impaired renal function. The excretion of chlorids and 

 nitrogen seems to be a fairly independent renal function. In contrast to 

 so-called parenchymatous nephritis, the function of excreting chlorids in 



