1813.] 



On Vomiting, 



437 



It remains to be known how an emetic introduced into the 

 stomach can affect the seat of the nervous energy in a manner 

 so as specifically to produce vomiting. Is it by irritating the 

 nerves of the stomach ? Or is it absorbed, introduced into the 

 bloody and transported by the circulation ? Perhaps both of 

 tiiese modes of transmission take place, according to circum- 

 stances. The vomiting whicii we observe son/,etimes after cutting 

 the nerves of the eighth pair, and which appears to be occasioned 

 by the irritation which the superior segment of these nerves 

 experiences, seems to favour the first mode of action; while the 

 experiments of M. Magendie producing vomiting even in ani- 

 mals deprived of their stomach, by injecting an emetic into the 

 blood-vessels, seems equally favourable to the second mode. His 

 preceding experiments on the effect of upas, experiments made 

 in concert v.ith M. Delille, strengthen this last opinion. They 

 prove that upas occasions those dreadful convulsions which so 

 speedily destroy life, only when it is absorbed into the mass of 

 the blood, and transported directly to the spinal marrow. It is 

 very probable that almost all substances that have some effect on 

 the animal oeconomy act in this manner. This opinion leads us 

 to views entirely new respecting the mode of action of most 

 medicines and poisons. 



Another question remaining to be answered, is to know the 

 precise part of the brain or spinal marrow on which the efforts 

 of vomiting depend. M. le Gallois has proved that the principle 

 of the movement of inspiration is seated in that portion of the 

 medulla oblongata which gives origin to the eiglith pair of 

 nerves. If we consider that the efforts of vomiting are executed 

 by the muscles of respiration, that the nerves of the eighth pair 

 supply the stomach as well as lungs, and that the disorder of the 

 medulla oblongata in apoplexy occasions vomiting, it will be 

 rendered pretty probable that the efforts of vomiting are situated 

 not far from those of respiration, if they have not the very same 

 position. But it would be of importance to determine the point 

 by direct experiments. Now that the general seat of the nervous 

 energy is well determined, and clearly defined, one of the 

 greatest objects of physiology is to know precisely the function 

 peculiar to the different portions of that seat. Such objects 

 deserve the attention of such accurate experimenters as MM. le 

 Gallois and Magendie ; and those experiments, which they have 

 already made so successfully, induce us to hope that they will 

 advance still farther in a career in which they know by expe 

 rience that they are likely to meet with honour, glory, and repu 

 tation. 



To conclude, we think, 1. That M. Magendie, to whom the 

 0ass Ims already given with so much pleasure proofs of its 



