CHAP. XI.] FUNCTIONS OF THE ENCEPHALON; 351 



olivary columns, however, are in great part continuations of the 

 thalami on the one hand, and of the gray matter of the cord on 

 the other ; and contain abundance of vesicular matter, in which 

 nerves are implanted. 



And it must be admitted, that the intimate connexion of sensation 

 and motion, whereby sensation becomes a frequent excitor of motion, 

 and voluntary motion is always, in a state of health, attended 

 with sensation, would a priori lead us to look for the respective 

 centres of these two great faculties, not only in juxtaposition, but in 

 union at least as intimate as that which exists between the corpus 

 striata and optic thalamus, or between the anterior and the 

 posterior horns of the spinal gray matter. 



Saucerotte, Foville, Pinel Grandchamps, and others, advanced 

 the opinion, that the corpora striata and the fibrous substance of 

 the anterior lobes of the brain had a special influence upon the 

 motions of the lower extremities, and that the optic thalami and 

 the fibrous substance of the middle and posterior part of the brain 

 presided over the movements of the upper extremities. We find, 

 however, but little to favour the theory either in the results of 

 experiments, in pathological observation, or the anatomy of the 

 parts. Longet states, that, in his experiments upon the optic 

 thalami, the paralysis affected equally the anterior and the posterior 

 extremities. Andral analysed seventy-five cases of cerebral lesion 

 limited to the corpus striatum or optic thalamus. In twenty-three 

 of these cases, the paralysis was confined to the upper extremity : 

 of these, eleven were affected with lesion of the corpus striatum or 

 of the anterior lobe ; ten with lesion of the posterior lobe, or of the 

 optic thalamus ; the two with lesion of the middle lobe.* Hence 

 it is plain that a diseased state of the corpus striatum is as apt to 

 induce paralysis of the upper extremity, as lesion of the thalamus ; 

 and we are forced to conclude, that pathological anatomy is not 

 competent to decide the question. Lastly, the anatomy of these 

 two bodies renders it highly improbable that they perform a 

 function so similar, as that of directing the movements of particular 

 limbs. The great size of the optic thalamus, its multitude of 

 librous radiations, its extensive connexions both in the medulla 

 oblongata and in the hemispheres by means of commissural fibres, 

 the marked difference of its structure from that of the corpus 

 striatum, its connexion more with the posterior horns of the spinal 

 gray matter than with the anterior ones, and its intimate relation 



* Clin.Med.t.v. 



