MICROBES, OR BACTERIA. 123 
XII. THe Microspes wHICH DESTROY BUILDING 
MATERIALS, 
The observations of Parize, director of the 
agronomic station, Morlaix, lead to the belief that 
microbes, which destroy dead bodies and effect such 
various transformations in nature, not only attack 
the beams of our houses, as we have already seen, but 
building materials of an inorganic nature, including 
stones. 
On one occasion, when Parize was examining some 
mucedinece which had vegetated on a brick partition, 
in a closed and somewhat damp recess, he noticed 
blisters on the coat of plaster. He broke one of these 
blisters, and a fine red dust, consisting of pulverized 
brick, issued from it. When placed in the micro- 
scope, under a magnifying power of about 300 
diameters, he saw, amid schistoid fragments, dia- 
tomatace and silicious algze pertaining to the original 
clay of the bricks, an immense number of living 
microbes: micrococcus, bacteria, amcebse, and ciliated 
spores of algae, moving rapidly in the drop of water 
used to moisten the dust. Some of these were in process 
of budding. These organisms existed under a coat 
of five to six mm. of plaster, and even of 30 mm. at 
the bottom of a hole pierced by the brace; but in this 
case they were less numerous, in the proportion of 
two to three. The germs and spores which exist 
