58 Dissection of Frog. 



brain underneath, at the same time care must be used 

 not to squeeze the eyes in holding the skull. When all 

 the upper part of the brain is laid bare, the bone should 

 be nipped through in front of it with the forceps, and 

 the base of the skull divided ; by gently cutting away 

 the bone by degrees and dividing the nerves proceeding 

 from the brain, it can be completely freed with the 

 cerebellum, pons, and medulla intact. 



It requires some practice and care to do this well, 

 but even if the brain is a little torn in removing it, 

 there will still be plenty to harden and make sections 

 of. The bone can now be cut through, round, and in 

 the orbit the optic nerve and recti muscles divided, and 

 the eye removed whole. 



Portions of nerve can be taken from different parts, 

 the optic, sciatic, &c. Portions of muscle may also be 

 cut out. The aorta and some of the larger arteries 

 should be removed and cleaned from the surrounding 

 tissues. 



DISSECTION OF FROG. 



The whole eye may be removed from a frog and 

 placed in Muller's fluid, but the cornea is required to 

 make a gold preparation. 



Having killed a frog, wrap it in a cloth and render 

 the eye tense with the thumb of the left hand. Insert 

 one of the points of a fine pair of curved scissors at the 

 edge of the cornea and cut it round carefully, separate 

 it from the rest of the eye, and place it in gold chloride. 



The mesentery and meso-gastrium may be prepared 

 by the silver process. 



