1S14.] Imperial Institute. 461 



sive contraction of the muscles which surround the belly, and this 

 contraction itself is excited by an irritation of the oesophagus. 



It was of importance to know what muscles act principally, what 

 nerves put them in action, and in consequence of what cause they 

 are irritated. To determine these points, M. Magendie in the irst 

 place cut or removed the abdominal muscles without much dimi- 

 nishing the activity of vomiting. On the other hand, when a great 

 part of its force is taken from the diaphragm by cutting the phrenic 

 nerves, onlv weak nauseas take place at long intervals, and vomiting 

 seldom takes place, notwithstanding the contraction of the abdo- 

 minal muscles. Thus the diaphragm acts by far the greatest part in 

 this compression. When the action of the diaphragm and abdo- 

 minal muscles is destroyed at once, vomiting does not take place, 

 even if the animal be made to swallow substances eminently emetic, 

 as corrosive sublimate. Finally, what seems almost a wonderful 

 corroboration of all these proofs, M. Magendie removed the stomach 

 entirely, and substituted a bladder in its place, which was attached 

 to the bottom of the oesophagus, by making it communicate with 

 that pipe by means of a solid tube, and after sewing up the abdo- 

 men he injected tartar emetic into the veins. The animal had 

 nauseas, made inspirations, and threw out a coloured liquid which 

 had been put into the bladder; just as would have happened had 

 the stomach been sound, and an emetic administered in the ordinary 

 way. 



Emetics, then, do not produce vomiting by irritating the fibres 

 of the stomach, nor even the nerves ; but in consequence of being 

 carried by absorption and circulation to the nervous system, and 

 exciting an action which reflects specifically on the oesophagus and 

 diaphragm, so as to produce in them different movements, among 

 which there are some the final result of which is the compression of 

 the stomach. This does not hinder vomifing from being produced 

 by the immediate irritation of the nerves of some one of these parts, 

 or by any nervous irritation which affects the system in a way similar 

 to an emetic. 



It remains for M. Magendie to distinguish with more precision 

 the part of the oesophagus and diaphragm concerned in the act of 

 vomiting, and to examine the phenomena of this motion in birds 

 and animals without a diaphragm. 



To his memoir on the action of antimony considered in a phy- 

 siological point of view, M. Magendie has added another on its 

 medical or deleterious action ; and he has .shown by many observa- 

 tions made on man, and by numerous experiments on the inferior 

 animals, that the tartrate of this metal taken in considerable quan- 

 tity is of itself a mortal poison ; but that its first effect is almost 

 always vomiting, which throw! out the greatest part of the poison 

 before it has time to produce a fatal effect. Heme molt of those 

 who have attempted to destroy themselves by this substance have 

 been disappointed in their object. 



M. Magendie hai likewise presented to the (lass a set of expert- 



