“When the ancestor, by any gift or conveyance, tak- eth an estate of freehold , and in the same gift or conveyance an estate is limited, either mediately or immediately , to his heirs in fee or in tail, the ‘heirs’ are words of limitation of the estate, and not words of purchase .” 1 Coke, 104. Intimately connected with the quantity of estate which a tenant may hold iu realty is the antique feudal doctrine generally known as the “Rule in Shelley’s Case,” which is reported by Lord Coke in 1 Coke, 936, (23 Eliz. in C. B.) This rule was not first laid down or established iu that case, but was then simply admitted in argument as a well- fouuded and settled rule of law , and has always since been quoted as the “Rule in Shel- ley’s Case.” Wharton.