7 16 



THE CEREBRAL CORTEX. 



excitation of the superior temporal convolution, which also produces 

 movement of the head and eyes to the opposite side, was found by 

 Ferrier to be accompanied by contraction of the pupils. The probability 

 is, since dilatation of the pupil is ordinarily associated with converg- 

 ence, and contraction with parallelism of the visual axes, that the 

 pupillary effects of cerebral stimulation vary according as such 

 stimulation tends to produce one or other of those conditions. 

 But the matter is one to which little attention has hitherto been 

 given. 



It is noteworthy that, although in birds Ferrier was unable to obtain 

 any movements of the limb or trunk muscles as the result of electrical 

 stimulation of the hemisphere, nevertheless stimulation of a point at the 

 vertex of the hemisphere produced " intense contraction of the opposite 

 pupil, occasionally associated with turning of the head to the opposite 

 side." 



Effects upon the secretions and upon involuntary muscular 

 tissue. — The effects of emotions upon the secretions, and especially the 

 secretions of saliva and sweat, and upon the muscular tissue supplied 

 through the sympathetic nervous system, especially that of the skin 

 and hairs of the alimentary canal and of the urinary bladder, render it 

 very probable that artificial excitation of the cortex should also produce 

 similar effects. That excitation of the cortex in the dog produces 

 a flow of saliva, was first shown by Bochefontaine, 1 who obtained it from 

 excitation of points scattered over the greater part of the motor area. 

 The effect was usually most marked upon the gland (the submaxillary 

 was employed) of the opposite side, but there was some secretion from 

 the gland of the same side ; the impulses passed by the chorda tympani. 2 

 There is also a marked flow as the result of artificially induced epilepsy. 3 

 So far as the secretion of sweat is concerned, simple excitation of the 

 cortex has yielded negative results, but Adamkiewicz has remarked the 

 occurrence of abundant perspiration in partial cortical epilepsy in man, 

 affecting the parts which were thrown into convulsions; and the same 

 has been noted in the foot of the cat as the result of artificially 

 produced epilepsy by Franck and Pitres. A certain number of observa- 

 tions have been made upon other secretions— urinary, gastric, biliary — 

 by Bochefontaine 4 and others, but these have been quite insufficient to 

 determine whether any direct or localised relation subsists between 

 special parts of the cortex and the secretions. The evidence is, on the 

 whole, unfavourable to the conclusion that there are such localised 

 relations, and the effects which are obtained seem to be produced by the 

 cortex as a whole acting upon the bulbo-spinal centres. 



Still fewer experiments have been made upon the influence of 

 the cortex upon the " organic " muscles. The only ones that need 

 here be referred to are those upon the bladder. Bochefontaine 5 

 found that excitation in the dog of certain points in the neighbour- 

 hood of the crucial sulcus produced evacuation of the contents 

 of the 1 (ladder in curarised animals. This observation has been 



1 Arch, dephysiol. norm, at path., Paris, 1876, p. 161. 



2 Of. on this subject, Eckhard, Bcitr. z. Anal. it. Physiol. (Eel-hard), Giessen, Bd. 

 vii. S. 199 ; and Neurol. Centralhl., Leipzig, 1889, S. 65 ; also v. Bechterew and Mislawski, 

 ibid., 1888, S. 553. Further references will be found in the article "Salivary Secretion," 

 by Langley, in the first volume of this work. 



a Albertoni, quoted by Francois-Franck, loc. cit., p. 240; also Francois-Franck and 

 Pitres, loc. cit. 4 Loc. cit. s Loc. cit. 



