101 



XXXII. ON APPARENTLY SPONTANEOUS ACTIONS OF THE CONTRAC- 

 TILE TISSUES OF THE ANIMAL BODY. 



All the contractile tissues of the animal body (the muscles of 

 the trunk and limbs, the muscular layers of the digestive canal, 

 the iris, the uterus, the dartos, the cellular tissue, etc.) present, 

 sometimes, apparently spontaneous contractions. I give this 

 name to contractions which are not the result of an external 

 excitation or of an excitation produced by the nervous system on 

 the contractile tissues. These contractions may be permanent 

 or momentary, rhythmical or irregular, slight or very powerful. 

 One of their causes, if not their only cause, appears to be an 

 excitation directly produced on the contractile fibres by the 

 carbonic acid existing in the blood. 



1. Contractions in the muscles of the face after a section of the 

 facial nerve. My friend Dr. Martin-Magron and myself have 

 discovered that after the section of one of the facial nerves, on a 

 rabbit, the face becomes very quickly deviated, not on the healthy 

 side, as it is known to be in man, but, strange to say, on the 

 paralysed side. The deviation, very slight at first, increases 

 gradually during one or two weeks, and then it is so considerable 

 that the middle of the lips is at a distance of four, five or six 

 lines from its natural situation. There is an evident state of 

 contraction in all the paralysed muscles. When the animal is 

 excited, or when its respiration is somewhat disturbed or pre- 

 vented, the paralytic muscles tremble, and sometimes they have 

 rhythmical contractions and relaxations. 



The contractions of these muscles may be so considerable that 

 the bones themselves, and, secondarily, the teeth, may be de- 

 formed. In one case, on a rabbit which I had kept living twenty- 

 one months after the extirpation of one of the facial nerves, not 

 only the superior and inferior jaws were by far less developed on 

 the paralysed side than on the other, but the anterior part of 

 the superior maxillary bone was deviated towards the paralysed 

 side, so that the middle line of the roof of the mouth was curved 

 and presented a great concavity on the paralysed side and a cor- 

 responding convexity on the other. 



When the two facial nerves have been divided, there is no 



