THE RABBIT. 119 



oblique. It is chiefly to these muscles that the oculomotor 

 series of nerves is distributed. The superior oblique and 

 posterior rectus are dignified by having a nerve each, 

 exclusively for themselves, viz. iv. for the former and vi. 

 for the latter. The rest, along with the iris and ciliary 

 muscles, have to be content with nerve in. divided 

 among them. 



A lachrymal gland lies in the postero-superior angle of 

 the orbit, and a Harderian gland in the corresponding 

 position in front : the secretion of these has a lubricating 

 function, enabling the eye to move easily in its orbit, and 

 washing away all dust, etc. The excess of the secretion 

 passes by a duct through the lachrymal bone into the nasal 

 chamber. In addition to the upper and lower eyelids of 

 the human subject, the rabbit has a third, the nictitating 

 lid, in the anterior corner of the eye. 



12. Functions of Brain, Before leaving the nervous 

 system we must briefly allude to the functions of the greatly 

 enlarged parts of the brain in the rabbit. The grey matter 

 of the cerebral hemispheres is the seat of consciousness and 

 the association of ideas, and from its nerve-cells impulses 

 are sent out which, as it were, give orders of a general kind 

 to subordinate parts of the central nervous system, these 

 subordinate parts translating these general orders into the 

 necessary detailed orders to the various active tissues. 

 Similarly it receives only, as it were, the most important 

 pieces of information as to what is going on in all parts 

 only those which are too important to be dealt with by 

 the subordinate centres. 



The chief function of the cerebellum is equilibration^ 

 or the balancing of the body. The normal position of a 

 rabbit's body is one of unstable equilibrium, as any one will 

 find who tries to place a dead rabbit in its normal living 

 posture. These normal postures (whether of rest or motion) 

 are only maintained in steadiness by constant action of 

 appropriate, muscles, just as a bicycle can only be kept 

 from wobbling on an uneven road by constant variations in 

 the pressure on the handles. The cerebellum is continually 

 receiving impressions from the retina and from the ampullae 



