124 DRAGON FLIES VS. MOSQUITOES. 



That the house fly is in some ways a menace to health 

 may be readily allowed. Scientific literature contains 

 many instances illustrating this fact. Dr. B. Grassi's ex- 

 periments (Archiv. Ital. Biol, IV., pages 205-208, and 

 Am. JSFat., XVIII., page 1267) show that flies are agents 

 in the diflnision of infections, maladies, epidemics, and 

 even parasitic diseases. Drs. Spillman and Hanshalter, in 

 a report made to the French Academy, have come to sim- 

 ilar conclusions. (Science, X., page 214, 1887.) Leidy 

 (Proc. Ac. N. Sc. Phil., 140, 1874) found a thread-like 

 worm infesting the house fly. This parasite was first dis- 

 covered in the house fly of India by Mr. H. J. Carter, 

 who described it under the name Filaria muscee, and sue:- 

 gested that it might be the cause pf the Guinea worm, 

 Filaria medinensis, in man. 



The house fly in its larval stages lives in manure and 

 other decaying vegetable matters. I would suggest the 

 speedy removal of all such matters in cities, and also the 

 refuse in houses, and under no circumstances should our 

 Board of Health allow the accumulation of manure for 

 shipment along our river fronts, as has been done in cer- 

 tain parts of New York City. 



Stables are the principal breeding grounds of the house 

 fly. Kerosene sprinkled over the floor in stables is said 

 to be an excellent remedy to keep flies away. 



The various instruments and methods to trap flies in 

 houses are too well known to discuss here. As a self 

 perpetuating remedy, and one allied to the natural means 

 discussed in reference to the mosquito, the fly fungus (Spo- 

 rendonema) might be employed and established to destroy 

 the house fly by inoculation. 



