96 Plasma Chlorides and Chloride Excretion 
provokes an increment in urinary excretion proportional to the 
square of the rise. The constancy of this threshold even under a 
prolonged régime of extremely high or extremely low chloride 
diet is again demonstrated in our experiments. In.the patho- 
logical kidney, however, there may be either an alteration in the 
threshold or a disturbance in the degree of renal response to in- 
crements in the plasma chlorides above the threshold. Because 
of these two variables interpretation of the significance of altera- 
tions in the chloride index in pathological cases is complicated. 
PROTOCOLS. 
Dog I.—Female, weight 14 kilos. 
Experiment 1.—Ordinary diet. On a mixed diet of table scraps. 
Water ad libitum. 
Experiment 1 A.—No food or water since previous day. 
Sept. 28, 11.40 a.m. Catheterized. Given 100 ce. of distilled water by 
stomach tube. 12.15 p.m. Bled 12cc. 12.40 p.m. Catheterized. Only 
1 cc. of urine obtained. Given 100 cc. of distilled water. 1.55 p.m. Ca- 
theterized. 160 cc. of urine (1385 minutes). N, 6.3; D, 0.85; E, 0.5. 
Experiment 1 B.—Sept. 28. 1.55 p.m. Given 100 cc. of 3 per cent so- 
dium chloride solution by stomach tube. 3.00 p.m. Given 100 ce. of 5 per 
cent, sodium chloride solution by stomach tube. Catheterized. 3.25. 
p.m. Bled 24 cc. 4.20 p.m. Catheterized. 135 cc. of urine (80 min- 
utes). N, 7.8; D, 34.5; HE, 14.2. 
Experiment 2.—High salt diet. Dog placed for 5 days (Sept. 29 to 
Oct. 3) on a diet of milk, 1 quart, and one dog biscuit each day. In ad- 
dition given each day (except Oct. 2) 150 cc. of 5 per cent sodium chloride 
solution by stomach tube. Water ad libitum. 
Experiment 2.A.—No food, water, or salt since previous day. 
Oct. 4, 2.45 p.m. Catheterized. Given 90 cc. of distilled water by 
stomach tube. 3.18 p.m. Bled 24 cc. 3.45 p.m. Catheterized. 15 cc. 
of urine (60 minutes). N, 6.7; D, 0.36; H, 1. 
Experiment 2 B.—Oct. 4, 3.45 p.m. Given 95 cc. of 5 per cent sodium: 
chloride solution by stomach tube. 4.43 p.m. Same dose of sodium 
chloride repeated.. Catheterized. 5.20 p.m. Bled 24 cc. 5.45 p.m. 
Catheterized. 140 cc. of urine (62 minutes). N, 7.4; D, 49.5; E, 15.2. 
Experiment 3.—Low salt diet. For 10 days (Oct. 18 to Oct. 27) on a 
low salt diet. (Milk, 1 quart, and dried salt-free bread.) In addition 
given each day 150 cc. of distilled water by stomach tube. 
Experiment 8 A.—No food or water since previous day. 
Oct. 28, 9.45 am. Catheterized. Given 100 cc. of distilled water i 
stomach tube. 10.20 a.m. Bled 16 ce. 10.50 a.m. Catheterized. 12cc. 
of urine (65 minutes). N, 6,3; D, 0.1; E, 0.4. 
