'Exhalations'

"The evidence is just as indubitable that exhalations arise from the bodies of the dead, which are capable of producing disease and death. Many instances are recorded of the communication of smallpox from the corpse of a person who has died of smallpox. This has happened not only in the dwelling house before interment, but even in the dissecting room. Some years ago five students of anatomy, at the Webb street school, Southwark, who were pursuing their studies under Mr. Grainger, were seized with smallpox, communicated from a on the dissecting table, though it does not appear that all who were attacked were actually  engaged in dissecting this body. One of these young men died. There is reason to believe that emanations from the bodies of persons who have died of other forms of fever have proved injurious and even fatal to individuals who have been much in the same room with the corpse."

From  : PRACTICE OF INTERMENT IN TOWNS EDWIN CHADWICK, (1843)