104 BRITISH REPTILES 
theirjprecious adder-oil. Spring is the time for that ; 
for, although the creatures have been in a semi- 
torpid state all the winter, they are fat when they 
crawl out to bask in the first warm sunshine. 
You may readily know where the oil-getters have 
been at work when you pass along, for there are 
the headless bodies] of the vipers hung on the twigs 
of the bushes that line the banks. No forester or 
forester's child ever^leaves the head on a viper ; it is 
cut off, as I said before, and ground into the earth 
to prevent accidents. The oil is firmly believed by 
them to have wonderful virtues, especially in the case 
of a bite from the creature itself, but I think plain 
olive oil would be quite as efficacious. 
We will now pass on to a more pleasing and per- 
fectly harmless member of the family, the common 
grass snake, Coluber natrix. This handsome and 
perfectly harmless creature, under favourable con- 
ditions, reaches the large size of from five to six feet 
in length specimens of from three to four feet long 
are very common ; the larger ones are found in waste 
places near the woods, where gravel or brick earth 
has been dug. The hollows, after the places have 
been abandoned, get filled with water, and the rough 
ground covered with wild tangle ; here their food 
is in abundance namely, frogs, mice, birds and 
