Beats me.Never heard this expressed as a Latin maxim and I can't find so much as 'you must take as you find' in any Law Dictionary of maxims in Latin.! You never know, if we trawl through Fred Lawton's judgment in Blaue, he might have used a Latin expression ,but that's doubtful because using Latin wasn't really his style.
In R v Blaue the victim died only because they'd refused a blood transfusion,it being contrary to their religion.It was argued that the defendant wasn't, therefore, responsible for the death itself. What had caused the death was the victim's refusal to take the blood transfusion .Lord Justice Lawton and his brother judges rejected that argument, as evidenced by the quote given by Buenchico ! (But we don't think it was ever said in Latin).