MICROBES, OB BACTERIA. 123 



XII. THE MICROBES 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- 

 tomatacese and silicious algae pertaining to the original 

 clay of the bricks, an immense number of living 

 microbes : micrococcus, bacteria, amoebae, 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 



