THE ADDER. 149 
uncurled, measured, and counted. The dissection 
must be made with some care to avoid injuring the 
eges, and the following is the method T adopt 
myself, 
Dissection of gravid female adders.—Fix the 
adder down on a board at the head end by ineans of a 
nail or drawing-pin through the snout, the adder being 
on its back, the belly exposed to the operator. Leave 
the body and tail free. The best instrument to use 
is an ordinary blunt-pointed sureical bistoury, which 
is a long thin-bladed knife with a blunt point. A 
sharp - pointed knife is very apt to injure the ab- 
dominal contents. Grasping the adder’s tail with 
the left hand, insert the blunt point of the knife 
into the aperture of the cloaca (the posterior opening 
on the belly, that is) and gently slit up the belly from 
behind forwards, keeping the edge of the knife in a 
line with the edge of the successive large ventral 
scales. Continue this incision for about half - way 
up the body, and then withdrawing the knife, turn 
the separated surface of the belly over to the side 
where it is still attached. The whole of the contents of 
the lower half of the body cavity will now be exposed. 
(rently separate the intestines with the handle of the 
knife, and the two large strings of eggs will be seen 
lying underneath, one row on each side of the cavity. 
Trace these up and down to their ends, and tie a 
ligature round the oviduct at each end, on each side 
—four ligatures altogether. The blood-supply to the 
