THE MICROBES 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.—Micrebes and spores of atmospheric dust, mixed with amorphous 
particles, and collected by the aéroscope. 
and of drawing general conclusions as to the hygienie 
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 
