E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Drop.
To take a drop. A eupnemism for taking what the drinker chooses to call by that term. It may be anything from a sip to a Dutchmans draught.
1
A drop of the cratur. In Ireland means a drink of whisky, or creature-comfort.
2
To take a drop too much. To be intoxicated. If it is the last feather which breaks the camels back, it is the drop too much which produces intoxication.