CHAPTER IX 

 DISTRIBUTION OF BACTERIA AND OTHER DISEASE GERMS 



111. Questions for Discussion. 1. What disease has caused the most 

 deaths in your community during the past year ? How was the disease 

 transmitted from one person to another? 2. What precautions are 

 taken in your community to secure pure water and milk? 3. What is 

 your community doing to decrease the number of flies? 4. Is your 

 home as well defended from flies as it should be ? 5. Is the breeding 

 of mosquitoes about your home prevented ? 6. If impure surface water 

 runs into a well from the top, is it necessary to draw all the water from 

 the well to purify it or only the first few feet at the top ? 7. Why is 

 expectoration on sidewalks and in street cars forbidden? What is 

 your state law on this question? 8. Why are there laws prohibiting 

 public drinking cups? 9. Baker's bread is handled by more people 

 befo r e being used than homemade bread. How does this affect the 

 probability of harmful bacteria's being present on this bread? 10. Which 

 is to be preferred, clean certified milk or ordinary milk which has been 

 pasteurized? 11. Why is machine-made ice often used in regions 

 where there is much cold weather as well as in regions that are warm ? 

 12. What are your state laws relative to quarantine in case of infectious 

 diseases ? Why should all urge that quarantine laws be enforced ? 



112. Means of distribution. However great may be the 

 injury which disease germs are capable of doing to each of 

 us, it is clear that no harm can actually result unless the 

 germs are carried by some means from those who are sick 

 to those who are well. It therefore becomes highly important 

 for all of us to know the means of distribution of disease 

 germs so that we may avoid them. We have seen that the 

 air is one means of distribution, but many others exist. Sub- 

 stances upon which bacteria are growing sometimes become 

 dry and powdered, as in the street dust of which we have 

 spoken. The bacteria are then blown about in air currents 

 and, with the remainder of the dust, settle wherever they may. 



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