INFLUENCE OF THE NEKVOTJS SYSTEM ON ABSORPTION. 467 



in thirty seconds. 1 In the same series of experiments, the 

 effects of excessive repletion of the vessels were demonstra- 

 ted. After injecting about a quart of water into the veins 

 of a dog of medium size, absorption was found to be con- 

 siderably retarded; and in another experiment, in which 

 more than two quarts of water were thus introduced (as 

 much as could be injected without producing death) the ab- 

 sorption of poisons seemed to be arrested ; and after having 

 waited half an hour for the phenomena which were generally 

 developed in two minutes, a large opening was made in the 

 jugular vein, and as the vessels became relieved, the toxic 

 effects were manifested. 2 



The rapidity of the circulation has an important influence 

 upon absorption. We have already shown, in treating of the 

 action of the blood-vessels on absorption, that this process 

 may be impeded or even arrested by the ligation of important 

 vessels. It has been evident, also, that absorption is generally 

 active in proportion to the vascularity of different parts. 

 During ,the process of intestinal absorption, the increase in 

 the activity of the circulation in the mucous membrane 

 is very marked, and undoubtedly has its influence upon the 

 rapidity with which the products of digestion are taken up. 



Influence of the Nervous System on Absorption. Experi- 

 ments upon the influence of the nervous system on absorption 

 are still very imperfect. It is certain that this process, espe- 

 cially in the stomach, is subject to variations, which can 

 hardly be dependent upon any thing but nervous action. 

 Water and other liquids, which usually are readily absorbed 

 from the stomach, are sometimes retained for a time, and are 

 afterward rejected in nearly the condition in which they were 

 taken. It is probable, however, that the most important in- 

 fluences thus exerted by the nervous system are effected 



1 MAGENDIE, Memoire sur le Mechanisme de T Absorption chez les Animaux d 

 Sang rouge et chaud. Journal de Physiologic, Paris, 1821, tome i., p. 5. 

 a MAGENDIE, loc. cit. 



