MECHANICAL PHENOMENA. 49 



exist in a variety of physiological reactions. RINGER l first 

 called attention to it in his experiments on heart muscle. He 

 found that the contractions of strips of this tissue, which are 

 beating rhythmically in sodium chloride solutions, can be 

 inhibited through the addition of a calcium salt to the sodium 

 chloride solution. The experiments of LOEB, who has elab- 

 orated those of RINGER, show that the same antagonism exists 

 in the case of voluntary muscles and in nerves. Experiments 

 of other investigators are at hand which show that the antag- 

 onism between calcium and sodium salts exists in the involun- 

 tary muscles also, but these experiments are not entirely free 

 from criticism, for no special means were taken to exclude the 

 effects of nerve fibres or nerve-cells present in the preparations. 

 Whether the increased peristalsis is brought about directly 

 through the action of the saline cathartics upon the muscle- 

 cells themselves or only indirectly through an action of the 

 salts upon the nerve plexuses of AUE REACH and MEISSNER has 

 not as yet been definitely settled. It is certain that we do 

 not need to go beyond the wall of the intestine for an ex- 

 planation of the action of these drugs. This is proven by the 

 fact that pieces of gut ligatured and cut out of the body will 

 show their characteristic movements when immersed in solu- 

 tions of the various salines. A secretion of fluid will even occur 

 into such pieces of intestine. This indicates that the ex- 

 planation of this phenomenon too does not lie beyond the 

 walls of the alimentary tract. From the fact that very 

 dilute solutions of the cathartics produce very violent and 

 yet entirely local contractions in the intestine when painted 

 upon its peritoneal surface it seems highly probable that the 

 increased peristalsis is brought about through a direct action 

 upon the muscular coat. If a stimulation of nerves lay at 

 the foundation of the increased intestinal movements we 

 would expect a more general effect from the local applica- 

 tions of the cathartic salts. 



1 RINGER: Journal of Physiology, 1884, V, p. 247. 



