CONDITIONS OF INTESTINAI ACTIVITY. 331 



obstruction of the aorta, causes or strengthens the intestinal contractions 

 (Schiff). 1 Nasse,' 2 Mayer and v. Basch 3 state that obstruction of the 

 aorta arrests the movements for a time, but they return afterwards 

 with increased vigour. Most observers (Betz, 4 v. Braam Houckgeest, 5 

 Mall), however, agree that anaemia inhibits all the movements of the 

 intestines, a view which I can confirm. If the rhythmical contractions 

 of the small intestines in the dog be recorded by the insertion of a small 

 balloon communicating with a piston recorder, obstruction of the aorta 

 in the chest causes an almost immediate cessation of the movements, 

 which lasts as long as the obstruction is continued (up to 15 minutes). 

 During this time the lever sinks slowly, i.e., there is a gradual diminution 

 of intestinal tonus. If, now, the blood be let in, the intestines contract 

 immediately, once or twice, then pause, and then recommence their 

 rhythmic movements, the contractions often increasing in force for a 

 couple of minutes. This recommencement is associated with a consider- 

 able diminution in the diastolic volume of the intestines, i.e. increased 

 tonus. Mall points out that ligation of the superior mesenteric 

 artery causes strong contractions. In this case the determining cause 

 appears to be, not the ischemia, but the hemorrhagic infarction which 

 is produced by the ligation, so that the ultimate effect resembles in some 

 extent that produced by venous obstruction. 



It is probable that the varying statements on this subject depend 

 on the frequent coincidence of anaemia and local asphyxia. The ex- 

 citatory effect of the circulation of venous blood through the intestines 

 has been frequently pointed out (Engelmann, v. Basch, etc.). In general 

 asphyxia, one may indeed observe a preliminary inhibition of intestinal 

 movements, but this is due to the splanchnic excitation, and consequent 

 anemia. I must confess, however, that I have often missed altogether 

 an excitatory effect of asphyxia on the intestinal movements, and have 

 only observed it in rabbits. 



Influence of the nervous system on intestinal movements. — 

 The intestines receive a rich nerve supply from the spinal cord, by 

 way of the sympathetic chain, great and small splanchnics (from 

 first three lumbar ganglia), and solar and mesenteric plexuses. They 

 also receive fibres from the vagus through the communicating 

 branches from the anterior and posterior gastric plexuses to the solar 

 plexus. 



Vagus. — A number of authors have described the vagus as the 

 motor nerves of the intestines. Thus stimulation of the vagus in the 

 neck has been said to evoke active contractions of both stomach and 

 intestines (Budge, 6 Ludwig and Kupffer, 7 Engelmann 8 ). According 

 to v. Braam Houckgeest, 9 the vagus has no direct action on the 

 intestines, the contractions being simply propagated from the stomach. 

 Mayer 10 states, however, that he has observed movements of the small 

 and large intestines on stimulation of the vagus, even after ligation of 

 the duodenum. There is no doubt that, in a number of cases, stimulation 



1 "Lehrbuch d. Physiologie," 1858-59, S. 105. 



2 "Beitr. z. Physiol, d. Darmbewegung," Leipzig, 1866. 



3 Sitzungsb. d. k. Akad. d. Wissemch., Wien, 1870, Bd. lxii. 



4 Firchow's Archiv, Bd. i. 5 Arch. f. d. yes. Physiol. , Bonn, 1872, Bd. vi. S. 266. 

 fi "Lehrbuch d. Physiologie," 1887, S. 225. 



7 Ztschr. f. rat. Med., 1858, Bd. ii. S. 357. 



8 Arch./, d. ges. Physio/., Bonn, 1871, Bd. iv. i Ibid., Bd. vi. 

 10 Hermann's " Handbuch," Bd. v. (2). 



