On the mechanism of the physiological action of the cathartics - John Bruce MacCallum

Loop contained in beginning	2.0 c.c.
Fluid secreted during 1st 10 minutes	0.8 c.c.
Fluid secreted during 2d 10 minutes	0.4 c.c.

2 c.c. m/8 CaCl₂ applied locally to serous surface.

Fluid secreted during 1st 10 minutes following application	0.0 c.c.
Fluid secreted during 2d 10 minutes following application	0.0 c.c.

4 c.c. m/8 sodium citrate applied locally.

Fluid secreted during 1st 10 minutes

0.6 c.c.

3. Rabbit. Loop 22 cm. long.

Loop contained in beginning	2.4 c.c.
Fluid secreted during 1st 10 minutes	1.2 c.c.
Fluid secreted during 2d 10 minutes	1.15 c.c.

3 c.c. m/8 MgCl₂ applied locally to serous surface.

Fluid secreted during 1st 10 minutes following application	0.0 c.c.
Fluid secreted during 2d 10 minutes following application	0.0 c.c.
Fluid secreted during 3d 10 minutes following application	0.2 c.c.

Although in these experiments the quantity of fluid secreted is small, there is a definite cessation of this excretion following the application of calcium or magnesium chloride. The subsequent administration of sodium citrate in each case causes the secretion to recommence.