140 OF FOOD, AND THE DIGESTIVE PROCESS. 



circulation. Kolliker, who admits the inhibitory power of the splanchnic.?, 

 states that it is destroyed by woorara ; and Brunton 1 was unable to perceive 

 it in several animals narcotized by chloral. 



97. The movements of the intestines appear further to be powerfully 

 affected by the quantity of blood supplied to them, as well as by its arterial 

 or venous. quality. Nasse observed lively movements, both when the vessels 

 were rendered anaemic by pi'essure on the aorta, and when blood was injected 

 at a high- pressure. S. Mayer and v. Basch 2 remark that compression of the 

 thoracic aorta usually, but not always, causes vigorous contraction both of 

 the longitudinal and circular muscular fibres of the intestines, which they 

 attribute to the excitation either of the peripheral extremities of the splanch- 

 nic and vagi, of the solar plexus, of the ganglia of the myenteric plexus, or 

 possibly even of the muscular fibres themselves, by the carbonic acid or 

 other product of disintegration, which accumulates in the stagnating blood. 

 They maintain that when such products are present, lively movements can 

 be induced by irritation either of the splanchnics or of the pueumogastrics ; 

 but that when absent, no amount of irritation of these nerves has any effect. 

 Both nerves, therefore, contain motor fibres for the intestines, which, however, 

 only act under certain conditions. 3 Hermann 4 remarks simply that saturation 

 of the blood with oxygen arrests the movements of the intestines, whilst satu- 

 ration with carbonic acid excites them, which explains to some extent their 

 activit}*- shortly after death. The whole subject requires to be reinvestigated, 

 since Horvath 5 has shown that temperature has a very powerful influence 

 in determining the reaction of the intestinal walls to electric stimulation. 

 No movements occur in the intestines according to this observer, when they 

 are cooled below 66 F., whilst they exhibit spontaneous movements, and 

 contract on the application of electricity between 66 F. and 106 F., at 

 which last temperature the movements are sometimes very vigorous and 

 rapid, supporting in Rabbits and Guinea-pigs a column of water 18 centim- 

 etres in height. Horvath, in opposition to the statements of Nasse, Legros, 

 and Onimus and Mayer, maintains that a certain fulness of the vessels is 

 absolutely necessary ; no contractions occuring in ansemia even at a high 

 temperature. The action of many aperient medicines, as Senna and Crotou 

 oil, has been demonstrated 6 to be due to their producing increased peristalsis : 

 if pushed too far, however, and if their action be very violent, they diminish 

 the irritability of the intestines and even cause paralysis, a fact not to be 

 overlooked in the administration of purgatives for the relief of constipation. 



1 Handbook for the Phys. Laboratory, 1873, p. 5213. 



2 Sitz. d. k. Akad. zu. Wien, B. Ixii", 1870, p 809. 



3 It is to be noted, however, that although the absence of arterial blood causes lively 

 contractions, none are produced by an excess of venous blood in the mesenteric veins, 

 such as may be occasioned by pressure on the vena portie. This fact is admitted by 

 Mayer and Basch, and has also been demonstrated by Legros and Onimus (Robin's 

 Journal de Physiol., 1809, pp. 37 and 163). It should also be stated that Van Braam 

 Houckgeest (Pfliiger's Archiv, 1872, p. 208), who operated carefully by opening the 

 abdomen whilst the animals experimented on were immersed in water containing 0.6 

 of common salt, at blood heat, maintains that ansernic conditions prevent, arrest, or 

 weaken the movements of the intestines, and that whilst distension of the vessels with 

 citluT arterial or venous blood favored contraction in the small intestines, the latter 

 condition alone seemed to increase the irritability of the nervo-muscular apparatus 

 of the large intestines in Rabbits. Sanders Exn (Humphry and Turner's Journal of 

 Anat., vol. vi, 1872, p. 242), operating in the same way as Houckgeest, maintains 

 that the amount of blood in the vessels lias no influence on the intestinal movements. 



Physiologic, 1874, p. 136. 



5 Centralblatt f. d Med. Wiss., 1873, p. 597 et seq. 



8 By Radziejcwsky, Archiv f. Anat. v. Physiolog., 1870; and Legros and Onimus, 

 loc. cit. 



