330 APPENDIX 



X. DESTRUCTION OF BRAIN OR OF BRAIN AND 

 SPINAL CORD (PITHING) IN THE FROG. 



When killing a frog for physiological or microscopical 

 purposes it is sometimes advisable to remove as much blood 

 as possible from the body and sometimes to lose as little blood 

 as possible. 



1. Pithing and bleeding, a. Cut off the head or the upper jaw 

 with the skull with one stroke of strong scissors, thrust a seeker 

 down the spinal canal ; squeeze the body upward gently to get 

 rid of the blood. 



b. Have ready a nearly straight seeker. Hold the frog in a 

 cloth, with the legs between the third and fourth fingers ; and 

 depress the head with the fore- finger. Thrust the point of a 

 scalpel into the depression immediately behind the skull and so 

 cut across the medulla. At once push the seeker into the brain 

 and destroy it; and destroy similarly the spinal cord. Blood 

 will flow copiously from the cut. Place the frog in a stream of 

 water from a tap, and gently squeeze the body upwards, till the 

 bleeding ceases. 



2. Pithing without bleeding. Have ready some small frag- 

 ments of cotton-wool, and fine-pointed forceps. Proceed as in 

 1, b, but as soon as the brain and cord are destroyed, thrust 

 one or more of the pledgets of wool into the cut to stop the 

 bleeding. 



3. Destruction of the brain only. Proceed as in 2, but 

 destroy the brain only. 



Before killing the frog in any of the preceding ways it may 

 be anaesthetized with ether or chloroform. Take 100 c.c. of 

 water, add 2 c.c. of ether or '2 c.c. of chloroform, shake well ; 

 in this place the frog ; the limbs will gradually relax, and it will 



