468 ABSORPTION. 



through the circulation. The recent experiments of Bernard 

 and others upon the sympathetic system of nerves and its 

 connection with the muscular coats of the small arteries, by 

 the action of which the supply of blood in different parts is 

 regulated, point out a line of experimentation which would 

 probably throw much light upon some of the important vari- 

 ations in absorption. "When it is remembered that the small 

 arteries may become so contracted under the influence of the 

 sympathetic system, that their calibre is almost obliterated, 

 of course retarding to a corresponding degree the capillary 

 and venous circulation in the parts, and, again, that through 

 the sympathetic nerves the same vessels may be so dilated as 

 to admit to a particular part three or four times as much 

 blood as it ordinarily receives, it becomes apparent that ab- 

 sorption may be profoundly affected through this system of 

 nerves. Unfortunately, there are as yet no definite experi- 

 ments upon these points. In the observations upon absorp- 

 tion after division of certain nerves by Brodie, Brachet, Lon- 

 get, and others, attention was always directed particularly to 

 the cerebro-spinal system, and many of the experiments, in- 

 deed, were made before much was known concerning the 

 functions of the sympathetic. 



As far as the influence of the cerebro-spinal system is 

 concerned, it has been ascertained that while section of 

 some of the nerves distributed to the alimentary canal will 

 slightly retard the absorption of poisonous substances, it is 

 never entirely arrested. Longet found that the operation of 

 strychnine injected into the stomach of a dog in which both 

 pneumogastric nerves had been divided was retarded about 

 five minutes ; but that the convulsions, when they occurred, 

 were fully as severe as in an animal which had received an 

 equal dose, without section of the nerves. 1 



1 LONGET, 2raite de Physiologic, Paris, 1861, tome i., p. 379. 



