2 
HOUSEHOLD BACTERIOLOGY . 
exclaimed, “Where does all the dust come from?” If 
a house be thoroughly cleaned from cellar floor to attic 
ridge, tightly closed for months or years, when re¬ 
opened dust will be found in great quantities. 
This is true even in the country, where perhaps a 
single house, removed from the highway, stands sur¬ 
rounded by grass and trees. 
The “housekeeping” of ships includes dusting. 
The officers’ quarters of the government ships are 
dusted regularly, although land may not be seen for 
months at a time. 
Dust-proof Scientists have tried to get a dust-proof room or 
Room or .... . . 
House house in which to carry on their experiments. This 
has required attention to location and site, that there 
should be no jar from traffic or vibration from winds; 
a careful preparation of the surrounding soil; numer¬ 
ous walls separated from each other and made largely 
of glass, carefully joined and hermetically sealed. The 
air admitted must be freed from its dust; all clothes 
ordinarily worn by the experimenter must be ex¬ 
changed for garments especially prepared and cared 
for, before he enters this to-be-dustless room. Even 
then all surfaces need to be slightly moist, that any 
stray speck of dust which has escaped all these guards 
may be caught and held. 
Necessity Such conditions as these can never be secured in 
of Dust 
ordinary life, so that dust will probably be present with 
us always. Indeed, it is probable that were all dust 
exterminated, life also would become extinct, for life 
in its most efficient forms needs light, and Tyndall 
