7i8 



Reading-Course for Farmers' Wives. 



means of particles of dust. We see the clouds by means of the moisture 

 in the air which collects about dust particles, and fogs are a mass of 

 water dust. These dust particles are only the conveyances for life 

 which we are to study. 



Every garden has its weeds. Where the seeds all come from is a 

 never-failing mystery to the gardener. These common garden weeds which 

 are visible to us may all be destroyed with a rake or a hoe. There are 



other weeds, however 

 that are invisible to 

 the naked eye, and the 

 gardens in which they 

 grow may be the food 

 on our tables, our own 

 bodies, the dust in our 

 houses, etc. The germs 

 from which these 

 weeds arise may be 

 floating in the air and 

 are so small that we 

 cannot see them. They 

 cling to the particles 

 of dust and are planted 

 in it. 



Let us study some 

 dust gardens. 

 The Dust Garden. — 

 dust-garden Glass boxes fi 1 1 e d 



loosely with glass cov- 

 ers through which much that goes on inside may be seen are shown in 

 Figures 42 and 43, 



One day they served as garden beds. The soil was a kind of 

 beef broth jelly. The seed was ordinary dust from an ordinary 

 room. 



The covered box had been baked for over an hour in a very hot oven. 

 The jelly had been steamed a number of times, until no possible living 

 thing could be therein. 



Fig. 42 shows a dust-garden planted after the room had been carefully 

 swept. 



When the cover was removed and the dust, raised by the broom 

 into the air, was allowed to settle on the soft sticky jelly, something 

 happened. 



Fig. 42. — What grc.^ 



