CHAP, xi.] FUNCTIONS OF THE ENCEPHALON. 355 



The upper and posterior part of the mesocephale has already been 

 referred to, as being most probably that part of the brain which is 

 most directly influenced by emotional excitement. Dr. Carpenter 

 appears to localize the seat of emotional influence more specially in 

 the corpora quadrigemina, and refers to certain fibres, which he con- 

 siders terminate in those bodies, as channels of emotional impulses. 

 Although we cannot agree with this able writer in this limitation of 

 the centre of emotion (so to speak), nor in the existence of a distinct 

 series of fibres for emotional acts, we think the arguments he ad- 

 vances are most applicable to that view which refers the influence of 

 emotion to the gray matter of this entire region, which is brought 

 into connexion with the spinal cord by the fibres of the anterior 

 pyramids, as well as probably through the continuity of the olivary 

 columns and the posterior horns of the spinal gray matter. 



Every one has experienced in his own person how the emotions 

 of the mind, whether excited by a passing thought, or through the 

 external senses, may occasion not only involuntary movements, but 

 subjective sensations. The thrill which is felt throughout the entire 

 frame when a feeling of horror or of joy is excited, or the involun- 

 tary shudder which the idea of imminent danger or of some serious 

 hazard gives rise to, are phenomena of sensation and motion excited 

 by emotion. The nerves which take their origin from the medulla 

 oblongata, mesocephale, or crura cerebri, are especially apt to be 

 affected by emotions. The choking sensation which accompanies 

 grief is entirely referrible to the pharyngeal branches of the glosso- 

 pharyngeal and vagi nerves, which come from the olivary columns. 

 The flow of tears which the sudden ocurrence of joy or sorrow is 

 apt to induce may be attributed to the influence of the fifth nerve, 

 which is also implanted in the olivary columns, upon the lacrymal 

 gland; or of the fourth nerve, which anastomoses with the lacrymal 

 branch of the fifth. The more violent expressions of grief, sobbing, 

 crying, denote an excited state of the whole centre of emotion, in- 

 volving all the nerves which have connexion with it, the portio dura 

 the fifth, the vagus, and glosso-pharyngeal ; and even the respiratory 

 nerves, which take their origin from the spinal cord, as the phrenic, 

 spinal accessory, &c. And laughter, "holding both his sides/ 

 causes an analogous excitation of the same parts of the central organ 

 and of the same nerves. The very different effect produced by the 



pass through the former. But, in truth, we know so little of the positive 

 relation of the nerves in question to the ganglia, that no argument, either for 

 or against the above view, can r6st upon such imperfect information. 



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