46 PHYSIOLOGY OF ALIMENTATION. 



tions of the descending colon are apparently not affected by 

 emotional states, for they do not relax in the excitement 

 which causes the other movements to cease. 



Inhibition of intestinal movement is not the only conse- 

 quence of excited mental states CANNON quotes the ex- 

 periments of ESSELMONT and FUBINI to show this. ESSEL- 

 MONT found that in the dog signs of emotion always markedly 

 increase the motor activities of the intestine, though only for 

 a few moments. FUBINI noted that fear brings about an 

 increased peristalsis. 



Finally, the fact must be mentioned that all movements of 

 the intestines go on during sleep in the same way as in the 

 waking hours. 



ii. On the Action of Saline Cathartics. According to the 

 generally accepted view those salts which are classed under 

 the head of the saline cathartics in the works on pharmacology 

 are believed to exert their action by preventing the absorption 

 of water from the intestinal contents as the latter pass through 

 the alimentary tract. In this way it is believed that the 

 ordinary inspissation into the compact faces which collect in 

 the lower bowel is prevented, and the intestinal tract is rid 

 of its contents in the form of very soft or even liquid stools. 



It seems from experiments recently carried out by J. B. MAC- 

 CALLUM 1 that this conception can no longer be looked upon as 

 the correct one. MACC ALBUM'S experiments were performed 

 chiefly on rabbits, but dogs and cats were also employed. 

 The salts used were sodium citrate, sulphate, tartrate, oxalate, 

 phosphate, and fluoride, barium chloride, and magnesium sul- 

 phate. These experiments have shown that the saline purga- 

 tives act not only when introduced into the intestine, but also 

 when injected subcutaneously or intravenously. They act 

 most powerfully, however, when applied directly to the peri- 

 toneal coat of the intestine. When 5 to 10 c.c. of a one- 



1 MACCALLUM, J. B.: American Journal of Physiology, 1903, X, p. 

 101; Pfliiger's Archiv, 1904, CIV, p. 421. 



