Cloth can contract midras [tumah if it measures] three [handbreadths] by three [handbreadths], and it can contract corpse-tumah [if it measures] three [fingerbreadths] by three [fingerbreadths]. Sack [can contract tumah if it measures] four [handbreadths] by four [handbreadths]; hide [can contract tumah if it measures] five [handbreadths] by five [handbreadths]; a mat [can contract tumah if it measures] six [handbreadths] by six [handbreadths]. [This measure applies] equally to midras [tumah] and to corpse-tumah. R’ Meir says: [Regarding] sack, its remnants [can contract tumah if they measure] four [handbreadths]; but initially, [it contracts tumah] when it has been completed.