336 DISSECTION OF THE RABBIT. 



as far as practicable, and the mutual relations of its several 

 parts demonstrated. This method is the best, and should be 

 followed whenever possible. If, however, it is intended to 

 perform the whole dissection on a single rabbit, it will be 

 found advisable somewhat to modify the order of proceeding. 



For most purposes, young immature rabbits are best for 

 dissection, but for the examination of the reproductive organs, 

 it is necessary to have specimens six months old. They may be 

 hilled by pouring a few drops of solution of cyanide of potas- 

 sium into the mouth, or else by chloroform, or by coal gas in a 

 lethal chamber. If cyanide is used the mouth must be well 

 washed after death. 



The brain should be removed at once and put into either 

 strong spirit, if required soon, or still better, into a mixture of 

 equal parts of one per cent, potass, bichromate and eight per 

 cent, formalin. This hardening fluid should be renewed at 

 least once, and allowed to act for three weeks. Then wash the 

 brain in running water for a day, and keep it in five per cent, 

 formalin. 



I. EXTERNA^ CHARACTERS. 



The whole body is covered with hairs variously coloured ; 

 and is obviously divided into head, neck, trunk, a short tail, 

 and two pairs of limbs. 



A. The Head. 



Note the general form of the head. Determine the position 

 of the mandible, the zygomatic arches, the supra-orbital pro- 

 cesses of the frontals, and other parts of the skull by feeling 

 through the skin. 



1. The mouth is a small transverse aperture on the under 



surface of the front of the head, bounded by the 

 soft hairy lips. The upper lip is divided by a 

 median cleft, which connects the mouth with the 

 nostrils, and leaves the upper incisors exposed. 



2. The nostrils are a pair of oblique slits at the end of the 



hairy snout. 



