176 PRACTICAL BOTANY 



people have been. Plenty of fresh air, sunshine, and whole- 

 some food are most important factors in preventing attacks 

 of tuberculosis, and these, together with good general vitality 

 of the body, are one's best guaranty against this disease. On 

 the other hand, poor food, bad air, dark rooms, and low vital- 

 ity render the body a favorable growing place for these disease 

 germs when once they are introduced. These predisposing 

 factors are of tremendous importance in relation to tubercu- 

 losis, and too much emphasis cannot be given them. The 

 nature of the occupation and habits of men have much to do 

 with predisposing and exposing them to tuberculosis. This 

 was proved by an Englishman named Newsholme, in 1898, 

 when by means of records he showed that for each 100 agri- 

 culturists who died from tuberculosis and other respiratory 

 diseases, there were 453 potters and earthenware workers, 407 

 cutters, 373 plumbers, and 335 glassmakers who died from 

 these same diseases. At a time when so much is known about 

 how to prevent tuberculosis it seems a needless waste of human 

 life to allow so many people to become affected by it. 



161. Prevention of disease. Bacteria are distributed into al- 

 most every nook and corner of the earth, in soil, air, water, 

 dust, and upon and within the bodies of plants and animals. 

 Disease-producing bacteria are common, though less abun- 

 dantly distributed than forms which do not cause disease. 

 A good deal is known regarding the methods of distribution 

 and infection of the most dangerous disease-producing forms, 

 though our knowledge is by no means complete. Polluted 

 water and milk have often been the means of wholesale dis- 

 tribution of typhoid germs (Fig. 151). The house fly is one 

 of the most dangerous agents of distribution of typhoid and 

 probably of other disease bacteria. The atmosphere is an 

 efficient means of carrying bacteria of tuberculosis. They 

 must, however, be dry in order that they may be thus carried. 

 Every possible effort should be made to remove the breed- 

 ing places of flies (refuse from stables, exposed and decaying 

 sewage, etc.) and to keep them out of public and private 



