124 PHYSIOLOGY. 



do not need to go into the street to be exposed. Who 

 knows what he brings into the house adhering to his 

 clothing ? These germs may be brought into the most 

 cleanly houses in this way, or by the wind. 



How to avoid the Danger. Now, of course, all such 

 material known to be highly dangerous ought to be de- 

 stroyed. If those suffering from such diseases were care- 

 ful to burn all such matter, most of the seeds of this disease 

 would be killed. Thus in time we might stamp out the 

 disease, as a scourge of Canada thistles. But so long as 

 people expectorate upon the floors and pavements it will 

 be difficult to prevent the spread of such germ diseases. 



In hospitals such matters are now looked after with the 

 greatest care, and in private houses where there is intelli- 

 gence on these subjects. And it is encouraging to note 

 the awakening of the public to the significance of the teach- 

 ings of modern science on this subject, as shown by the 

 fact that many of the railroad and street car companies 

 now prohibit spitting on the floors of cars, not merely be- 

 cause it is uncleanly, but on the express ground that it is a 

 means of spreading infectious diseases. 



Bacteria. These disease germs are the smallest and 

 simplest of living things. They are plants ; and while all 

 of them that are well known have their scientific names, 

 just as the larger plants have, they are all included in one 

 general group designated as bacteria. 



How to avoid Dust. We need to learn a good deal 

 more about avoiding and destroying dust, and the things 

 that make dust. 



Towns and cities need more sprinkling to keep the dust 

 down. Much more of the refuse and street sweepings and 



