592 



I have found that the olivary tract of the medulla ohlongata is 

 both sensitive and motor, although it is not, as I have tried to prove 

 elsewhere, a leader for sensibility and voluntary movements. 



II. Some experiments which I made two or three years ago, 

 and many that I have recently performed, show that the lateral 

 columns of the spinal cord in the neighbourhood of the medulla ob- 

 longata, and a part of the anterior gray matter, are the principal, if 

 not the only channels for voluntary movements in that region. 

 Lower down in the spinal cord (in the dorsal and lumbar regions), 

 the anterior columns and the gray matter seem to have alone the 

 function of conductors for voluntary movements. If a transverse 

 section be made of one of the lateral columns with almost the whole 

 of the anterior horn of gray matter, about an inch behind the medulla 

 oblongata, we find voluntary movements almost completely lost on 

 that side. If a transverse section be made of one of the anterior 

 columns of the spinal cord, an inch behind the medulla oblongata, 

 we find that voluntary movements are not much diminished ; 

 and, as in this case, we divide also a part of the gray matter, and 

 frequently a part also of the lateral column, it seems that the ante- 

 rior column there has but little to do with voluntary movements. 

 Other experiments lead to the same conclusion; I will relate the 

 following alone : the anterior columns of the cord, when arrived at the 

 medulla oblongata, are known to send most of their fibres into the 

 lateral parts of this nervous centre, where they may be divided easily. 

 I have found, after the transverse section of the lateral column of 

 the medulla oblongata, that the voluntary movements are very little 

 diminished, and sometimes hardly at all. 



Besides, if we divide longitudinally the medulla oblongata, where 

 the pyramids cross each other, we find that the voluntary move- 

 ments are completely lost in both sides of the body. There are 

 convulsive and reflex movements, but no spontaneous regular move- 

 ment, and the animals, when put on their feet, fall on one side or 

 the other. 



From these facts and many others, it seems : 

 1st. That the anterior pyramids of the medulla oblongata con- 

 tain most of the voluntary motor nerve-fibres. 



2nd. That in the cervical region of the spinal cord, the voluntary 



