312 ELEMENTARY PHYSIOLOGY. [XXX. 



g. Immediately anterior to this a small area 

 the tuber cinereum, from this springs 

 the funnel-shaped infundibulum leading 

 to the round pituitary body- cut across 

 the infundibulum and observe the central 

 space, which leads into the third ventricle. 

 (The pituitary body may have been torn 

 away in removing the brain from the skull.) 



li. The optic tracts, two flat bundles of fibres 

 coming obliquely forward over the front part 

 of the crura cerebri, and meeting in the 

 middle line to form the optic chiasma: 

 from this a small piece of the optic nerve 

 will be seen coming off on each side. 



G. Observe the division of the cerebellum into a 

 median and two lateral lobes, cut through the 

 middle peduncle ( 5, 6) on each side where it 

 passes from the cerebellum, and remove the cere- 

 bellum; divide it into four pieces two by a longi- 

 tudinal and a transverse cut and note, the depth of 

 its fissures, the white substance radiating out- 

 wards in the laminae, and covered by a thin layer 

 of grey substance, the whole having a distinctly 

 arborescent appearance. In the midst of the cen- 

 tral mass of white substance in the lateral lobes 

 may be seen a greyer area representing the 

 corpus dentatum of man ; it is more distinct in 

 a brain preserved in ammonium bichromate. 



7. Observe now more closely the exposed fourth 

 ventricle. It has a roughly rhomboidal shape; 



