m/6 NaCl injected Time intravenously Urine 10:15 10:20 10 c.c. 2 c.c. 10:25 20 c.c. 4 c.c. 10:30 20 c.c. 6 c.c. 10:35 10 c.c. 7.5 c.c. 10:40 10 c.c. 8.0 c.c. 10:45 10 c.c. 8.2 c.c. 10:50 10 c.c. 7.9 c.c. 10:56 Injected 2 c.c. ¹⁄₂₀% saponin in m/6 NaCl 11:00 10 c.c. 10.5 c.c. 11:05 10 c.c. 11.0 c.c. 11:10 10 c.c. 11.0 c.c. 11:15 10 c.c. 11.0 c.c. 11:16 Injected 1 c.c. ¹⁄₂₀% saponin 11:20 10 c.c. 12.2 c.c. 11:25 10 c.c. 13.2 c.c. 11:30 10 c.c. 12.0 c.c. 11:35 10 c.c. 12.5 c.c. It is possible that it is by no means a coincidence that these substances which are powerful haemolytics act also as diuretics; and that CaCl_{2} and MgCl_{2}, which inhibit the secretion of urine, also to some extent inhibit the haemolytic action. It is difficult to say by what process the haemoglobin is liberated from the red blood corpuscle, as indeed it is difficult to state definitely how fluid passes from the blood into the urine. It is sufficient to call attention to the fact that the liberation of haemoglobin and the flow of urine may be to some extent controlled by the same conditions. If the haemolytics such as saponin cause haemolysis by increasing the permeability of the membranes of the red blood corpuscles, it seems possible that the diuretic effect of these substances may be due to a similar process in the kidney. If this be true, changes in permeability must play an important part in the action of these diuretics. And it is not impossible that the inhibition of the haemolytic action of saponin, etc., as well as the inhibition of the flow of urine by CaCl_{2} and MgCl_{2}, may be due to a decreased permeability of the red blood corpuscle on the one hand, and of the kidney cells on the other. With these numerous experiments with calcium and magnesium it is still impossible to make a general statement as to the nature of their action. Since the chemical conditions existing in the tissues of animals and of various parts of animals are largely a matter of conjecture, we cannot predict how these substances will act; nor can we say that because calcium, for example, has a certain action in one animal or on one organ it will necessarily have the same action in other animals or in other organs.