There are also, without their towns, places appointed near some running water for killing their beasts and for washing away their filth, which is done by their slaves; for they suffer none of their citizens to kill their cattle, because they think that pity and good-nature, which are among the best of those affections that are born with us, are much impaired by the butchering of animals; nor do they suffer anything that is foul or unclean to be brought within their towns, lest the air should be infected by ill-smells, which might prejudice their health.