THE MICKOBES OF HUMAN DISEASES. 159 



to the physician and to the professor of hygiene, who 

 are anxious to decide on the precise cause of great 

 epidemics in order, if possible, to foresee and avert 

 them. This new branch of meteorology has been 

 termed atmospheric micrography, since it necessarily 

 involves the use of the microscope. 



The Microbes of the Atmosphere. In the observa- 

 tory of Montsouris, Paris, there is now a special 

 laboratory under the direction of Miquel, with the 

 object of studying the living organisms of the air, 

 of establishing statistics of their times and seasons, 



Figs. 74, 75. Microbes and spores of atmospheric dust, mixed with amorphous 

 particles, and collected by the aeroscope. 



and of drawing general conclusions as to the hygienic 

 condition of the air, according as it is more or 

 less charged with the microbes and spores which 

 are factors of disease. This laboratory is provided 

 with the apparatus necessary for such kinds of 

 research. 



The first of these apparatus serves to collect the 

 living organisms which are always mingled with a 

 large amount of inert dust (Figs. 74, 75). The 



