1 86 John Bruce MacCallum, M. D. 



In this case i cc "/s BaClg gradually suppresses the flow of 

 urine, and no trace of the strong diuretic action of barium is seen. 

 And, further, calcium chloride has here an action which seems at 

 first glance entirely opposed to that which it ordinarily has. As 

 shown in the previous experiments, calcium characteristically sup- 

 presses the secretion of urine. In this case the flow of urine 

 increases after its administration. These apparent contradictions 

 may be explained in the following way. In discussing the actions 

 of calcium and barium on the intestine, it was pointed out that 

 barium chloride, like the other saline purgatives, affects the in- 

 testine in two ways, namely, by increasing the peristaltic move- 

 ments and by increasing the secretion of fluid into the lumen. At- 

 tention was further called to the violent character of the muscular 

 contractions in the intestine caused by barium, which may so con- 

 strict the lumen of the intestine that fluid cannot pass from one 

 part to another. It was also shown that calcium to some extent 

 counteracts the action of barium both on the muscle, and on the 

 glands of the intestine. It seems therefore probable that the 

 increase in the flow of urine caused by small doses of barium 

 chloride {yi cc. ""/« solution) is due to an increase in the secretory 

 activity of the kidney entirely analogous to that which is pro- 

 duced in the intestine by the same salt. The cessation of the flow 

 of urine however which follows the administration of larger doses 

 of barium chloride (icc. "/g solution) is in all probability due 

 to the action of the barium on the muscle coats of the urinary pas- 

 sages, especially those of the calyces and pelvis of the kidney, and 

 those of the ureter. Since all of these various parts of the urinary 

 passages are surrounded by thick, circular and longitudinal muscle 

 coats, not unlike those of the intestine, it seems conceivable that 

 a strong contraction of these coats, such as barium is capable of 

 causing in the intestine might effectually shut off the lumen so 

 that no urine could pass. Furthermore the action of calcium in 

 renewing the flow of urine under these circumstances is quite 

 analogous to its action in suppressing the peristaltic movements 

 or in relieving the constrictions in the intestine caused by barium. 

 The actions of calcium and barium which are shown in Table 5, 

 are on the muscle coats of the urinary passages. It is quite conceiv- 



