Complete the summary below. Choose ONE WORD ONLY from the passage for each answer.

Ventilation in 19th-century hospital wards

Professor Alan Short examined the work of John Shaw Billings, who influenced the architectural [6] of hospitals to ensure they had good ventilation. He calculated that [7] in the air coming from patients suffering from [8] would not have harmed other patients. He also found that the air in [9] in hospitals could change as often as in a modern operating theatre. He suggests that energy use could be reduced by locating more patients in [10] areas. A major reason for improving ventilation in 19th-century hospitals was the demand from the [11] for protection against bad air, known as [12]. These were blamed for the spread of disease for hundreds of years, including epidemics of [13] in London and Paris in the middle of the 19th century.