The Action of Saline Cathartics. — By N. B. Dreyer, B. A. 

 (Cape et Oxon.), M. A. (Oxon.), Assistant Professor, 

 Department of Physiology, Dalhousie University, Halifax, 

 N. S. 



(Presented 29 March, 1926) 



Compounds, like sodium sulphate, magnesium sulphate 

 and sodium phosphate (Naj HPO4), are used extensively for 

 mild purging. They are given in hypertonic solutions, so that 

 on their entry into the gut, water is withdrawn from the tissues 

 into the lumen of the gut. This increases the volume of the in- 

 testinal contents, and results in strong peristaltic movements. 

 The increased activity of the alimentary canal, combined with 

 non-absorption of the salts and water, gives rise to a fluid stool. 



In the experiments described below, observations were 

 made not only on peristaltic, but also on segmental movements. 

 At the s^me time the amount of fluid injected into the gut lumen 

 was compared with that recovered at the end of any given period. 

 This was done to determine if any increase in intestinal content 

 occurred under the action of these salines. 



The method adopted was described by Babkin' some years 

 ago. It has the advantage over others commonly in use that 

 the muscle of the intestinal wall is only slightly injured locally 

 when inserting the cannulae, and further it does not interfere 

 with the blood supply. 



In all cases decerebrate cats were used, the vagi and splan- 

 chnic nerves were cut, and the bile and pancreatic ducts were 

 ligated. These ducts were tied so that no secretion from liver 

 or pancreas could enter the duodenum, as this was the portion 

 of gut selected for the experiment. When all the operative 

 technique was completed the cat was immersed in a bath of 

 saline kept at 37° C. The intestines were by this means kept 

 covered and were at constant temperature. Movements 

 were recorded with a fairly large piston recorder. In addition 

 naked eye appearances were noted. Movements recorded under 

 the influence of 0.9% sodium chloride for periods of five to ten 

 minutes served as the normal. Small quantities varying from 



(1) B. P. Babkin. Bulletin de 1' Academie Imperiale des Sciences, 1916 



