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opened. It is in consequence of such movements that there is 

 an expulsion of faecal matters, after death, in man. The urine 

 may be also expelled in these cases, in man and in animals, and 

 this expulsion takes place because the bladder contracts, and not, 

 as it is generally admitted, because the sphincter vesicce becomes 

 relaxed. 



Some physiologists have considered the cessation of the circula- 

 tion of the blood in the bowels as the cause of their movements, 

 after death, and they relate as a proof the fact that the section of 

 one of the arteries going to a part of the intestines, is followed by 

 contractions in the parts thus deprived of circulation. But no- 

 thing is explained by saying that the cause of the contraction is 

 in the absence of circulation. As contractions require an exci- 

 tation to be produced, what is the exciting cause when the blood 

 does not circulate ? After the section of an artery there is blood 

 remaining in the capillaries, and that blood, after a short time, be- 

 comes very rich in carbonic acid, and then, if my theory is right, 

 contractions ought to be produced. The result of the section of 

 one of the arteries is, therefore, in accordance with my theory. 



Other facts may be adduced proving the influence of black 

 blood and carbonic acid on the bowels. 



If black blood is injected in the arteries of the small intestine 

 when its irritability is much diminished, movements are almost 

 immediately produced, but they do not last long. On the con- 

 trary, if red blood is injected, movements do not appear immedi- 

 ately, and they are very strong and last long. This action of 

 red blood may be easily understood : it increases the irritability 

 of the muscular layer of the bowels, as it does for that of the 

 muscles of animal life, and when it has been changed into black 

 blood, it excites the muscular tissue and produces contraction. 

 The strength and the long duration of the contraction in this 

 case depend on the increase of irritability. When, as in the 

 above experiment, black blood (containing a great quantity of 

 carbonic acid, on account of the constant formation of that gas 

 in blood deprived of the contact of atmospheric air) is injected, 

 the irritability is not sensibly increased, but the excitation is con- 

 siderable and there is an almost immediate effect. 



If air is injected in the arteries of the bowels, soon after the 

 death of the animal, a part of the blood it contains is expelled, 



