William Farr, médecin, et membre du Scientific Committee for Scientific Enquiries in Relation to the Cholera Epidemic reformule la théorie des miasmes contre les hypothèses microbiennes de John Snow.
Le Lancet soutient violemment cette position:
"Why is it then, that Dr. Snow is singular in his opinion? Has he any fact to show in proof? No! But he has a theory, to the effect that animal matters are only injurious when swallowed! The lungs are proof against animal poisons; but the alimentary canal affords a ready inlet. Dr. Snow is satisfied that every case of cholera for instance, depends upon a previous case of cholera, and is caused by swallowing the excrementitious matter voided by cholera patients. Very good! But if we admit this, how does it follow that the gases from decomposing animal matter are innocuous? We cannot tell. But Dr. Snow claims to have discovered that the law of propagation of cholera is the drinking of sewage water. His theory, of course, displaces all other theories. Other theories attribute great efficacy in the spread of cholera to bad drainage and atmospheric impurities. Therefore, says Dr. Snow, gases from animal and vegetable decompositions are innocuous! If this logic does not satisfy reason, it satisfies a theory; and we all know that theory is often more despotic than reason. "