He judged the Creoles honest but lazy and illeducated, their town ugly and filthy though his horror at the city's sanitation was understandable; he would lose two wives to yellow fever in New Orleans.
The Creoles' town was filthy because they didn't have sanitation.
mnli hypothesis: The Creoles' town was filthy because they didn't have sanitation. premise: He judged the Creoles honest but lazy and illeducated, their town ugly and filthy though his horror at the city's sanitation was understandable; he would lose two wives to yellow fever in New Orleans.