BODY TISSUES AND FLUIDS 453 



chronic (interstitial) nephritis appears to be much less impaired than ex- 

 creting nitrogen. Consequently a restriction in the chlorid intake in the 

 latter condition may fairly quickly restore the chlorids to normal. In fact, 

 it is sometimes noted that when cases with marked nitrogen retention 

 are put on a restricted chlorid diet, the blood chlorids fall to a subnormal 

 level, such as is occasionally found in severe diabetes. A possible ex- 

 planation for this is that, owing to the large amounts of urea and sugar 

 present in the blood in these conditions, less chlorid is needed to maintain 

 normal osmotic conditions. The high chlorid figures for whole blood in 

 anemia and low figures in Asiatic cholera find probable explanation on 

 the basis of the relatively high proportion of the plasma in the former dis- 

 order and the reverse condition in the latter. 



Phosphates. The presence of phosphorus in the blood in lipoid form 

 has long been recognized, but exact data regarding the inorganic phos- 

 phorus is of more recent origin. In 1915 Green wald (c) reported observa- 

 tions on the acid-soluble (largely inorganic) and lipoid phosphorus of hu- 

 man blood serum. He observed that normally the acid-soluble phosphorus 

 as P varied between 2 and 6 mg. per 100 c.c., but that in severe nephritis 

 it might be considerably increased. A year later Marriott and Howland (a) 

 confirmed these observations and pointed out that the retention of (acid) 

 phosphate would seem to be sufficient to account for the degree of acidosis 

 observed. Recently Denis and Minot (#) have studied the inorganic phos- 

 phates of the plasma in a large series of pathological conditions. In con- 

 ditions other than nephritis and cardiorenal disease figures varying from 

 1.2 to 3.1 mg. of P per 100 c.c. of plasma were found, while in one case 

 of uremia figures exceeding 40 mg. were observed. They believe that 

 the determination of the inorganic phosphate of the plasma gives promise of 

 being of considerable prognostic value in renal and cardiorenal disease, 

 since fatal cases which they examined showed a rapidly rising plasma 

 phosphate. 



An idea of the distribution of the various phosphorus compounds of 

 normal human blood may be obtained from the table on page 454 taken 

 from Bloor(/i,) (the figures have been recalculated to terms of P). 



As is evident from the table below the phosphoric acid compounds of 

 human blood may be divided into two classes: (1) the acid-soluble solu- 

 ble in dilute acids and precipitated with the proteins by alcohol-ether 

 and (2) the lipoid-phosphoric acid compounds soluble in alcohol-ether 

 and precipitated with the proteins by dilute acids. These two groups are 

 apparently sharply defined and since their sum is practically equal to 

 the total phosphates, the presence of other forms of phosphorus in blood 

 in significant amounts is doubtful. Inorganic phosphates and an un- 

 known compiound which on decomposition by heating with acid yields phos- 

 phoric acid are present in the first group, while substances of the type 

 of lecithin are found in the second group (lecithin has already been dis- 



