DISSECTION OF THE PIGEON 411 



VIII. EXAMINATION OF THE BBAIN. 



A. Semoval of the Brain. 



Gut throiLgh the skin of the top of the head along the middle 

 line, and turn the flaps aside. Expose and scrape clean the 

 bones of the roof of the skull. Slice off with a scalpel the 

 skull-roof, taking care not to injure the brain, which Ues very 

 close to the bone. 



Gut away, bit by bit, the roof and sides of the skull, with 

 the scalpel and stout scissors, so as to expose the brain 

 thoroughly. Remove the neural arches of the first two vertebrce, 

 and divide th^ spinal cord transversely. Turn out the brain 

 carefully, cutting across the several nerve-roots one by one. 

 Place the brain in a bottle of strong spirit, with a pad of loose 

 cotton-wool at, the bottom, and lea/ve it for two or three days 

 until it is thoroughly hardened. .Examine it in water or in 

 weak spirit. 



B. External Characters of the Brain. 

 1. The dorsal surface. 



a. The cerehral hemispheres are a pair of large pyri- 



form bodies, closely applied to each other in the 

 median plane. Their surfaces are nearly smooth, 

 and their anterior ends bluntly pointed. 



b. The olfactory lobes are a pair of small conical bodies, 



projecting forwards from the anterior ends of the 

 hemispheres. 



c. The pineal body is a small oval body, immediately 



behind the hemispheres, and in the angle between 

 them. 



d. The optic lobes are a pair of smooth ovoid bodies at 



the sides of the brain, behind and rather below the 

 hemispheres. 



e. The cerebellum is a median elongated oval body, 



marked by a number of transverse fissures. In 

 front it is in contact with the hemispheres ; 

 behind, it overlaps the meduUa ; and laterally, it 

 lies above the optic lobes. 



