Quote from Camille Flammarion

Camille Flammarion wrote in 1872: While absorbing for our lungs the amount of air due to them, we often breathe without knowing it from the armies of microscopic animalcules suspended in the atmospheric fluid… In phenomena related to the body of plants and animals, these substances are so held, of such diverse origin, of which the air is the vehicle, probably exert a much more pronounced action than is commonly assumed… It is not to go too far forward to attribute to them part of the insalubrity that usually manifests itself in large urban areas of men.

Epidemic spreading miasmas are caused by air currents… The mortality that was so considerable in Paris during the first months of this year 1870 as a result of smallpox, pleurisy and chest flow has occurred mainly in the northern districts where the southerly winds bring the miasmas of the big city and where ozone disappears almost completely. Knowledge of public health conditions will be provided in part by the study of meteorology with variations in this health which constantly oscillates with the light breeze blast as well as under the weak balancing of barometric pressure.