THE HOUSE FLY IN RELATION TO OUR HOME 133 



the deaths of about 100,000 people. This is due to the filthy 

 habits of flies. Probably most of the dysentery and sum- 

 mer complaint, especially of babies, is due directly to flies, 

 for they carry directly to baby's milk on their legs or bodies 

 germs which they have 

 taken from some other 

 sick baby or person hav- 

 ing the disease. 



Typhoid fever, a well- 

 known disease, responsi- 

 ble for a great many 

 deaths, especially in 

 country districts, is un- 

 doubtedly largely spread 

 by means of flies. A 

 study of the accompany- 

 ing diagram will show 

 clearly that the warm 

 weather, spread of ty- 

 phoid, and diarrhoea are coincident with fly time. A 

 knowledge of the life history of the fly will help us to 

 combat the pest. 



Experiment. To work out the life history of the fly. 



Materials: A small wire cage. A piece of stale meat. 



Method: Leave the meat out in the open where there are plenty of flies 

 until you can see fly eggs, then cover it with a wire cage and keep it 

 in a warm place. 



Observation: Look at it every few days. What different stages follow 

 the egg stage ? How long does it take each stage to develop ? Do you 

 think temperature would have any effect on the rapidity of develop- 

 ment? 



Conclusion: What is the life cycle of the fly? 



Application: Does this experiment suggest any method of control of the 

 number of flies about the house ? 



There were 329 cases of typhoid in Jacksonville, 

 Florida, in 1910; 158 in 1911; and 87 in the 

 first 10 months of 1912. During the winter of 

 1910-1911, 80 to 85 % of the outdoor toilets 

 were made flyproof . How would you account 

 for the great decrease in cases of typhoid in- 

 dicated in 1911 and 1912 ? 



