THE PARTS OF THE BRAIN BELOW CEREBRAL 

 CORTEX, VIZ. MEDULLA OBLONGATA, PONS, 

 CEREBELLUM, CORPORA QUADRIGEMINA, AND 

 REGION OF THALAMUS. 



By C. S. Sherrington. 



Contents. — The Myelencephalon or Region of the Medulla Oblongata, 

 p. 884— The Root Cell Systems in, p. 884— The Bulbo-spinal Frog, p. 886— The 

 Bulbo-spinal Mammal, p. 886 — "Centres" in the Bulb, p. 887 — Conduction 

 Paths in the Bulb, p. 888 — The Metencephalon or Region of the Pons 

 Varolii and Cerebellum, p. 890 — Reactions in the Frog, p. 890 — And Rabbit, 

 p. 890— The Pons, p. 891— The Root Cell Systems in, p. 891—" Centres " in, 

 p. 891 — Conduction Paths in, p. 893 — The Cerebellum, p. 893 — -Excitation of, 

 p. 893 — Lesions of, Unilateral Ablation, p. 895 — Ablation of the whole 

 Cerebellum, p. 897 — Destruction of the Middle Lobe, p. 898 — Longitudinal 

 Bisection, p. 898 — Ablation in the Bird, p. 898 — Ablation in Lower Verte- 

 brates, p. 899 — Phenomena caused by Section of the Cerebellar Peduncles. — 

 Section of Anterior Peduncle, p. 900 — Section of Middle Peduncle, p. 900 — ■ 

 Section of the Posterior Peduncle, p. 901 — Bilateral Section of the Peduncles, 

 p. 901 — Phenomena of Cerebellar Origin in Human Disease, p. 901 — 

 Inferences drawn from Comparative Anatomy, p. 902 — Functions of the 

 Cerebellum, p. 903 — The Mesencephalon or Region of the Corpora 

 Quadrigemina, p. 911 — The Root Cell Systems in, p. 911 — Excitation of the 

 Corpora Quadrigemina, p. 912 — Reactions of Animals after Ablation of all the 

 Encephalic Regions in front of the Mesencephalon, p. 912 — Lesions of the 

 Corpora Quadrigemina, p. 912 — Decerebrate Rigidity, p. 913 — Conduction 

 Paths through the Mesencephalon, p. 915 — The Diencephalon or Region of 

 the Optic Thalamus, p. 916 — Visual Connections of, p. 916 — Excitation of, 

 p. 917 — Destructive Lesions of, p. 917. 



The Myelencephalon or Eegion of the Medulla Oblongata. 



The roof of this portion of the encephalon contains neither nerve 

 cells nor nerve fibres. From the present point of view, therefore, it is 

 functionless. The floor, on the other hand, forms the bulb, and exercises 

 manifold neural functions. 



Belonging to the afferent root cell system of this part are the ganglion cells 

 nf the nervus intermedius (geniculate ganglion), receiving impulses, perhaps 

 gustatory, from the tongue region ; the ganglion cells of the cochlear and vesti- 

 bular nerves, conducting impulses from the organs for hearing, geotropism and 

 space-relations of the head ; the ganglion cells of glosso-pharyngeal and vagus 

 nerves, conducting impulses from alimentary and respiratory mucous mem- 

 branes and from heart ; and occasionally ganglion cells belonging to the hypo- 

 glossal nerve, their distribution being unknown. The afferent root cell system 

 of this region brings no impulses from skin, except from a tiny patch at the 



