460 Proceedings of Philosophical Societies. [Dec. 



place just as speedily as if the upas had heen applied to the animal 

 in a state of integrity. But perhaps some may object that when the 

 upas was introduced into the intestine we may always suppose that 

 some lymphatics remained concealed, and that when it was applied 

 to the feet it was placed in a wound where it could penetrate into 

 the blood by open veins, and that this is not what is meant when 

 venous absorption is spoken of, for then we mean an action ascribed 

 to the veins in their natural state, and by means of their organic 

 pores. What is very remarkable in the experiments of MM. 

 Magendie and Delille is, that the blood of an animal already 

 poisoned, and just dying, transfused into the veins of another 

 animal, does not kill it, and scarcely occasions any perceptible 

 inconvenience. 



M. Magendie has made another very interesting application of 

 this action of certain substances introduced into the blood. 



It is known that tartar emetic injected into the veins of an animal 

 makes it vomit in a few minutes, while the same substance when 

 swallowed requires an hour to produce the same effect. Hence it 

 follows that the convulsive movement does not depend on the 

 immediate action of tartar emetic on the coats of the stomach. 

 Observations made on the viscus itself during the act of vomiting 

 had led some physiologists farther. They had perceived that the 

 walls of the stomach experience very little agitation, and hence had 

 concluded that it is not in the irritation of these walls that the 

 immediate cause of vomiting resides. But their opinion, which was 

 feebly supported, had been almost forgotten since Lieutaud and 

 Haller had rendered the contrary hypothesis prevalent. 



M. Magendie, wishing to ascertain the truth, employed the 

 convenient method of injections ; and having at first made an 

 opening into the abdomen , lie ascertained by the touch that, during 

 vomiting, the stomach itself remains in a state of inactivity; but 

 that at each nausea it is violently compressed by the contraction of 

 the diaphragm, and of the muscles of the belly. Farther, the long 

 inspirations which precede each vomiting introduce a sufficient 

 quantity of air to prevent its size from diminishing, notwithstanding 

 the quantity of matter thrown out. If the abdomen be sufficiently 

 opened to allow the stomach to come out altogether, the nauseas 

 continue, but produce no effect, because the muscles that contract 

 no longer act upon the stomach. If the stomach be replaced, 

 vomiting begins immediately : yet compression alone is not suffi- 

 cient; for if we compress with the hands the stomach of a dog thus 

 displaced, to which no emetic has been administered, we expel 

 indeed the contents of the stomach, but do not occasion true 

 vomiting ; because there is neither nausea nor those inspirations 

 which characterize that kind of convulsion. But if we stroke the 

 stomach instead of compressing it, and if the strokes extend to the 

 oesophagus, nausea and all the other symptoms of vomiting are 

 produced without administering any emetic. Thus vomiting would 

 m to result from the compression of the stomach by a convul- 



